Microsoft Coding Interview Questions

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microsoft interview questions

Microsoft Array Questions

Question 1. Trapping Rain Water Leetcode Solution Problem Statement The Trapping Rain Water LeetCode Solution – “Trapping Rain Water” states that given an array of heights which represents an elevation map where the width of each bar is 1. We need to find the amount of water trapped after rain. Example: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: Check ...

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Question 2. Partition to K Equal Sum Subsets Leetcode Solution Problem Statement The Partition to K Equal Sum Subsets LeetCode Solution – “Partition to K Equal Sum Subsets” states that you’re given the integer array nums and an integer k, return true if it is possible to have k non-empty subsets whose sums are all equal. Example: Input: nums = [4,3,2,3,5,2,1], k = 4 Output: ...

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Question 3. Coin Change 2 Leetcode Solution Problem Statement The Coin Change 2 LeetCode Solution – “Coin Change 2” states that given an array of distinct integers coins and an integer amount, representing a total amount of money. We need to return the count of the total number of different possible combinations that sum to the amount.  ...

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Question 4. Frog Jump Leetcode Solution Problem Statement The Frog Jump LeetCode Solution – “Frog Jump” states that given the list of stones (positions) sorted in ascending order, determine if the frog can cross the river by landing on the last stone (last index of the array). Initially, the frog is on the first stone and ...

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Question 5. Unique Paths II Leetcode Solution Problem Statement The Unique Paths II LeetCode Solution – “Unique Paths II” states that given the m x n grid where a robot starts from the top left corner of the grid. We need to find the total number of ways to reach the bottom right corner of the grid. ...

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Question 6. Search a 2D Matrix II Leetcode Solution Problem Statement The Search a 2D Matrix II LeetCode Solution – “Search a 2D Matrix II”asks you to find an efficient algorithm that searches for a value target in an m x n integer matrix matrix. Integers in each row, as well as column, are sorted in ascending order. Example: Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 5 Output: true ...

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Question 7. Maximum Length of a Concatenated String with Unique Characters Leetcode Solution Problem Statement The Maximum Length of a Concatenated String with Unique Characters LeetCode Solution – “Maximum Length of a Concatenated String with Unique Characters” says that you’re given an array of strings and you need to choose any subsequence of the given array and concatenate those strings to form the ...

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Question 8. Shortest Word Distance Leetcode Solution Problem Statement The Shortest Word Distance LeetCode Solution – says that you’re given an array of strings and two different words. We need to return the shortest distance between these two words that appear in the input string. Example: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "coding", word2 = "practice" Output: 3 Explanation: Word “coding” occurs at position 4. ...

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Question 9. Moving Average from Data Stream Leetcode Solution Problem Statement The Moving Average from Data Stream LeetCode Solution – “Moving Average from Data Stream” states that given a stream of integers and a window size k. We need to calculate the moving average of all the integers in the sliding window. If the number of elements in the ...

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Question 10. Set Matrix Zeroes Leetcode Solution Problem Statement The Set Matrix Zeroes LeetCode Solution – “Set Matrix Zeroes” states that you’re given an m x n integer matrix matrix.We need to modify the input matrix such that if any cell contains the element  0, then set its entire row and column to 0‘s. You must do it in ...

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Question 11. Missing Number Leetcode Solution Problem Statement The Missing Number LeetCode Solution – “Missing Number” states that given an array of size n containing n distinct numbers between [0,n]. We need to return the number which is missing in the range. Example:   Input:  nums = [3,0,1] Output: 2 Explanation: We can easily observe that all the ...

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Question 12. Design a Stack With Increment Operation Leetcode Solution Problem Statement The Design a Stack With Increment Operation Leetcode Solution –  states that we need to design a stack that supports the below operations efficiently. Assign the maximum capacity of the stack. Perform the push operation efficiently, if the size of the stack is strictly less than the maximum capacity of ...

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Question 13. Shuffle the Array Leetcode Solution The problem Shuffle the Array Leetcode Solution provides us with an array of length 2n. Here 2n refers that the array length is even. We are then told to shuffle the array. Here shuffling does not mean that we need to randomly shuffle the array but a specific way is ...

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Question 14. 3Sum Leetcode Solution Problem Statement Given an array of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Notice: that the solution set must not contain duplicate triplets. Example #1 [-1,0,1,2,-1,4] ...

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Question 15. Insert Interval Leetcode Solution The problem Insert Interval Leetcode Solution provides us with a list of some intervals and one separate interval. Then we are told to insert this new interval among the list of intervals. So, the new interval might be intersecting with intervals that are already in the list, or it might ...

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Question 16. Combination Sum Leetcode Solution The problem Combination Sum Leetcode Solution provides us an array or list of integers and a target. We are told to find the combinations that can be made using these integers any number of times that add up to the given target. So more formally, we can use the given ...

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Question 17. Island Perimeter Leetcode Solution Problem Statement In this problem, we are given a grid in form of a 2-D array. grid[i][j] = 0 represents there is water at that point and grid[i][j] = 1 represents land. Grid cells are connected vertically/horizontally but not diagonally. There is exactly one island (a connected component of land ...

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Question 18. Maximum Subarray Leetcode Solution Problem Statement Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example nums = [-2,1,-3,4,-1,2,1,-5,4] 6 Explanation: [4,-1,2,1] has the largest sum = 6. nums = [-1] -1 Approach 1 (Divide and Conquer) In this approach ...

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Question 19. Find N Unique Integers Sum up to Zero Leetcode Solution The problem Find N Unique Integers Sum up to Zero Leetcode Solution, provides us with an integer. It asks us to return n unique integers that sum up to 0. So, the question is pretty simple to understand. So, before diving into the solution. Let us take a look at ...

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Question 20. Partition Array Into Three Parts With Equal Sum Leetcode Solution The problem Partition Array Into Three Parts With Equal Sum Leetcode Solution provides us with an array or vector and asks if there are three partitions possible of the sequence. Here, by partition we mean that is there two indices i, j such that the sum of elements from start ...

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Question 21. Find Common Characters Leetcode Solution Problem Statement In this problem, we are given an array of strings. We need to print a list of all characters that appear in every string in the array(duplicates included). That is if a character appears 2 times in every string, but not 3 times, we need to have it ...

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Question 22. Find All Numbers Disappeared in an Array Leetcode Solution Problem Statement In this problem, we are given an array of integers. It contains elements ranging from 1 to N, where N = size of the array. However, there are some elements that have disappeared and some duplicates are present in their place. Our goal is to return an array ...

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Question 23. Majority Element II Leetcode Solution In this problem, we are given an array of integers. The goal is to find all the elements which occur more than ⌊N / 3⌋ time in the array where N = size of the array and ⌊ ⌋ is the floor operator. We need to return an array of ...

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Question 24. Relative Sort Array Leetcode Solution In this problem, we are given two arrays of positive integers. All elements of the second array are distinct and are present in the first array. However, the first array can contain duplicate elements or elements that are not in the second array. We need to sort the first array ...

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Question 25. Pascal’s Triangle II Leetcode Solution Problem Statement In this problem we have been given Row index(i) of the Pascal Triangle. We have to create a linear array containing the values of the ith row and return it. Row index starts from 0. We know that Pascal’s triangle is a triangle where each number is the ...

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Question 26. Unique Paths Leetcode Solution The problem Unique Paths Leetcode Solution states that you are given two integers representing the size of a grid. Using the size of the grid, the length, and breadth of the grid. We need to find the number of unique paths from the top left corner of the grid to ...

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Question 27. Number of Good Pairs Leetcode Solution Problem Statement In this problem an array of integers is given and we have to find out the count of total number of good pairs (a[i], a[j]) where a[i]=a[j]. Example nums = [1,2,3,1,1,3] 4 Explanation:   There are 4 good pairs at indices (0,3), (0,4), (3,4), (2,5) . [1,1,1,1] 6 Explanation:  ...

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Question 28. Find Lucky Integer in an Array Leetcode Solution Problem statement In the problem ” Find Lucky Integer in an Array ” we are given an array where an integer is called lucky if its frequency in the array is equal to its value. Our task is to return the largest lucky number. If no such number exists we ...

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Question 29. Balanced Binary Tree Leetcode Solution A binary tree is Height-balanced if the difference of heights of left and right subtree of every node in the tree is at most 1. In this problem, we are going to check for a balanced binary tree. Example 2 / 1 / 4 Not balanced 1 / \ 2 ...

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Question 30. Merge Sorted Arrays Leetcode Solution In the problem “Merge Sorted Arrays”, we are given two arrays sorted in non-descending order. The first array is not fully filled and has enough space to accommodate all elements of the second array as well. We have to merge the two arrays, such that the first array contains elements ...

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Question 31. Search in Rotated Sorted Array Leetcode Solution Consider a sorted array but one index was picked and the array was rotated at that point. Now, once the array has been rotated you are required to find a particular target element and return its index. In case, the element is not present, return -1. The problem is generally ...

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Question 32. Search Insert Position Leetcode Solution In this problem, we are given a sorted array and a target integer. We have to find its Search Insert Position. If the target value is present in the array, return its index. Return the index at which the target should be inserted so as to keep the order sorted(in ...

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Question 33. Plus One Leetcode Solution Problem statement In the problem ” Plus One”  we are given an array where each element in the array represents a digit of a number. The complete array represents a number. The zeroth index represents the MSB of the number.  We can assume that there is no leading zero in ...

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Question 34. Kth largest element in an Array Leetcode Solutions In this problem, we have to return the kth largest element in an unsorted array. Note that the array can have duplicates. So, we have to find the Kth largest element in the sorted order, not the distinct Kth largest element. Example A = {4 , 2 , 5 , 3 ...

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Question 35. Kth Missing Positive Number Leetcode Solution Problem statement In the problem “Kth Missing Positive Number” we are given an array arr, which is sorted in strictly increasing order and a number k. Our task is to find out the Kth positive missing number in the array. Example arr = [1,2,3,4], k = 2 6 Explanation: As ...

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Question 36. Guess Number Higher or Lower II Problem Statement “Guess Number Higher or Lower II” states that we are going to play a game that is called Guess Game. The game says that I pick a number from 1 to n. Whenever you guess the number which I have not picked, I m going to say you ...

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Question 37. Queries for Number of Distinct Elements in a Subarray We have given an array of integer and a number of queries and we have to find out the number of all the distinct elements we have within the given range, the query consists of two numbers left and right, this is the given range, with this given range we ...

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Question 38. Minimum swaps required to bring all elements less than or equal to k together The problem “Minimum swaps required to bring all elements less than or equal to k together” states that you have an integer array. The problem statement asks to find out the smallest count of swaps that will be required to get the elements together which are less than or equal ...

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Question 39. Find First and Last Position of Element in Sorted Array Leetcode Solution Problem statement In this article titled “Find First and Last Position of Element in Sorted Array Leetcode Solution,” we will discuss the solution to a leetcode problem. In the given problem we are given an array. We are also given a target element. Elements in the array are sequenced in ...

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Question 40. Best Time to Buy and Sell Stock  II Leetcode Solution Problem statement In the problem “Best Time to Buy and Sell Stock  II,” we are given an array where each element in the array contains the price of the given stock on that day. The definition of the transaction is buying one share of stock and selling that one share ...

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Question 41. Find Sum of all unique sub-array sum for a given array Suppose you have an array of integers. The problem “Find Sum of all unique sub-array sum for a given array” asks to find out the sum of all unique sub-arrays (Sub-array sum is the sum of each sub-array’s elements). By unique sub-array sum, we meant to say that no sub-array ...

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Question 42. Longest subarray not having more than K distinct elements The problem “Longest subarray not having more than K distinct elements” states that suppose you have an array of integers, the problem statement asks to find out the longest sub-array that having not greater than k different elements. Example arr[] = {4, 3, 5, 2, 1, 2, 0, 4, 5} ...

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Question 43. Construct Binary Tree from given Parent Array representation The problem “Construct Binary Tree from given Parent Array representation” states that you are given an array. This input array represents a binary tree. Now you need to construct a binary tree on the basis of this input array. The array stores the index of parent node at each index. ...

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Question 44. Find any one of the multiple repeating elements in read only array the problem “Find any one of the multiple repeating elements in read only array” states that suppose you are given a read-only array of size (n+1). An array is containing the integers from 1 to n. Your task is to find out any one of the repeated elements in the ...

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Question 45. Find four elements that sum to a given value (Hashmap) The problem “Find four elements that sum to a given value (Hashmap)” states that suppose, you have an integer array and a number called sum. The problem statement asks to determine if four elements present in the array which sums up to the given value “sum”. If true, then function ...

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Question 46. Longest subsequence such that difference between adjacents is one The problem “Longest subsequence such that difference between adjacents is one” states that you are given an integer array. Now you need to find the length of longest subsequence such that the difference of adjacent elements is 1. Example 1 2 3 4 7 5 9 4 6 Explanation As ...

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Question 47. Print all subarrays with 0 sum You are given an integer array, your task is to print all the possible sub-arrays with sum is equal to 0. So we need to Print all subarrays with 0 sum. Example arr[] = {-2, 4, -2, -1, 1, -3, 1, 5, 7, -11, -6} Sub-Array found from 0 index ...

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Question 48. Longest Bitonic Subsequence Suppose you have an array of integers, the problem statement asks to find out the longest bitonic subsequence. The bitonic sequence of an array is considered as the sequence which first increases and then decreases. Example arr[] = {1,4,2,76,43,78,54,32,1,56,23} 7 Explanation 1 ⇒ 4 ⇒ 76 ⇒ 78 ⇒ 54 ...

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Question 49. Check in binary array the number represented by a subarray is odd or even The problem “Check in binary array the number represented by a subarray is odd or even” states that you are given a binary array and a range. The array consists of the number in the form of 0s and 1s. The problem statement asks to find out the number represented ...

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Question 50. Gold Mine Problem Problem Statement The “Gold Mine problem” states that you are given a 2D grid having some non-negative coins placed in each cell of the given grid. Initially, the miner is standing at the first column but there is no restriction on the row. He can start in any row. The ...

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Question 51. Longest Increasing Consecutive Subsequence Subsequences are another topic loved by interviewers. Tweaking them around can always give them new opportunities for testing candidates. It can check the candidate’s ability to think and analyze things and come up with the best and optimal solutions. Today we are solving a subsequence problem that will be doing ...

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Question 52. Best Time to Buy and Sell Stock Problem Statement The problem “Best Time to Buy and Sell Stock” states that you are given an array of prices of length n, where the ith element stores the price of stock on ith day. If we can make only one transaction, that is, to buy on one day and ...

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Question 53. Top K Frequent Elements Problem Statement In top K frequent elements we have given an array nums[], find the k most frequently occurring elements. Examples nums[] = {1, 1, 1, 2, 2, 3} k = 2 1 2   nums[] = {1} k = 1 1 Naive Approach for Top K Frequent Elements Build ...

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Question 54. Sort an array according to the order defined by another array Problem Statement You are given two arrays of integers arr1[] and arr2[]. The problem “Sort an array according to the order defined by another array” asks to sort the first array according to the second array so that the numbers in first array will be relatively sorted off all the ...

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Question 55. Minimum time required to rot all oranges Problem Statement The problem “Minimum time required to rot all oranges” states that you are given a 2D array, every cell has one of the three possible values 0, 1 or 2. 0 means an empty cell. 1 means a fresh orange. 2 means a rotten orange. If a rotten ...

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Question 56. Maximum Product Subarray Problem Statement The problem “Maximum Product Subarray” states that you are given an array of integer containing both positive and negative numbers. The problem statement asks to find out the maximum product of the sub-array. Example arr[] = { 2, -2, 3, 5} 15 Explanation The elements in the sub-array ...

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Question 57. Find Minimum In Rotated Sorted Array Problem Statement “Find Minimum In Rotated Sorted Array” states that you are given a sorted array of size n which is rotated at some index. Find the minimum element in the array. Example a[ ] = {5, 1, 2, 3, 4} 1 Explanation: If we arrange the array in sorted ...

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Question 58. Implementation of Deque using circular array Problem Statement “Implementation of Deque using circular array” asks to implement the following functions of a Deque(Doubly Ended Queue) using circular array, insertFront(x) : insert an element x at the front of Deque insertRear(x) : insert an element x at the rear of Deque deleteFront() : delete an element from ...

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Question 59. Double the first element and move zero to end Problem Statement Suppose you have an array of integers. Here “0” is not a number which is considered as an input. It is not valid input here. The problem “Double the first element and move zero to end” asks to rearrange the array in such a way if a number ...

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Question 60. Find the first repeating element in an array of integers Problem Statement Find the first repeating element in an array of integers problem states that you are given an array of integer. It asks to find out the first repeating element from the array and print that number. Example arr[] = {2,6,9,3,1,9,1} 9 Explanation: In the given array there are ...

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Question 61. Check given array of size n can represent BST of n levels or not Problem Statement Given an array with n elements, check given array of size n can represent BST of n levels or not. That is to check whether the binary search tree constructed using these n elements can represent a BST of n levels. Examples arr[] = {10, 8, 6, 9, ...

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Question 62. Largest rectangular sub-matrix whose sum is 0 Problem Statement Find the maximum size sub-matrix in a 2D array whose sum is zero. A sub-matrix is nothing but a 2D array inside of the given 2D array. So, you have a matrix of signed integers, you need to calculate the sum of sub-matrices and find the matrix with ...

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Question 63. Maximum Sum Increasing Subsequence Problem Statement You are given an array of integers. Your task is to find out the maximum sum subsequence within the array in such a way that the numbers in subsequence should be ordered in a sorted manner in increasing order. A subsequence is nothing but a sequence that we ...

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Question 64. Largest Sum Contiguous Subarray Problem Statement You are given an array of integers. The problem statement asks to find out the largest sum contiguous subarray. This means nothing but to find a subarray (continuous elements) which has the largest sum among all other subarrays in the given array. Example arr[] = {1, -3, 4, ...

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Question 65. Matrix Chain Multiplication In the matrix chain multiplication II problem, we have given the dimensions of matrices, find the order of their multiplication such that the number of operations involved in multiplication of all the matrices is minimized. Consider you have 3 matrices A, B, C of sizes a x b, b x ...

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Question 66. Sorted Array to Balanced BST In sorted array to balanced BST problem, we have given an array in sorted order, construct a Balanced Binary Search Tree from the sorted array. Examples Input arr[] = {1, 2, 3, 4, 5} Output Pre-order : 3 2 1 5 4 Input arr[] = {7, 11, 13, 20, 22, ...

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Question 67. Subset Leetcode In Subset Leetcode problem we have given a set of distinct integers, nums, print all subsets (the power set). Note: The solution set must not contain duplicate subsets. An array A is a subset of an array B if a can be obtained from B by deleting some (possibly, zero ...

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Question 68. Shuffle an Array Given an array or set which contains n elements. Here the elements are unique or there is no repetition. Shuffle an array(or a set) of numbers without duplicates. Example // Init an array with set 2, 4, 3 and 1. int[] nums = {2, 4, 3, 1}; Shuffle object = ...

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Question 69. Dividing Array into Pairs With Sum Divisible by K The dividing array into pairs with sum divisible by K is a problem which is asked in interviews with various tweaks now and then. Those who know me know my habit of converting these problems into stories. In this article let us look into this problem. Situation To Understand The ...

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Question 70. Count Distinct Elements in Every Window of Size K Subsets are something which we have been dealing with for some time now. In the last episode, we covered the number of subsets we could make with distinct even numbers. This time we count distinct elements in every window of size K. Section-1 About the problem. Given an unsorted array ...

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Question 71. Word Search Word search is something like the word-finding puzzles at some time in our life. Today I bring to the table a modified crossword. My readers must be a bit perplexed as to what I am talking about. Without wasting any more time let us get to the problem statement Can ...

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Question 72. Insert Delete GetRandom In Insert Delete GetRandom problem we need to design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element from the current set ...

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Question 73. Merge Overlapping Intervals In merge overlapping intervals problem we have given a collection of intervals, merge and return all overlapping intervals. Example Input : [[2, 3], [3, 4], [5, 7]] Output: [[2, 4], [5, 7]] Explanation: We can merge [2, 3] and [3, 4] together to form [2, 4] Approach for finding Merge ...

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Question 74. Median of Two Sorted Arrays Given two sorted arrays A and B of size n and m respectively. Find the median of the final sorted array obtained after merging the given two arrays or in other words, we say that find median of two sorted arrays. ( Expected time complexity: O(log(n)) ) Approach 1 for ...

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Question 75. Maximum Product Subarray In the maximum product subarray problem, we have given an array of integers, find the contiguous sub-array with atleast one element which has the largest product. Example Arr=[ 0, -1, 0 ,1 ,2, -3] Maximum product = 2 Arr=[-1, -1, -1] Maximum product = -1 Arr=[0, -1, 0, -2, 0] ...

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Question 76. Minimum Size Subarray Sum Given an array nums of a positive integer and a sum s, find the minimum size of a contiguous subarray of nums such that whose sum equals to or greater than s(given value). Example Input: nums[] = {2, 3, 1, 2, 4, 3} s = 7 Output: 2   {Subarray [4, ...

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Question 77. Search an Element in Sorted Rotated Array In search in sorted rotated array problem we have given a sorted and rotated array and an element, check if the given element is present in the array or not. Examples Input nums[] = {2, 5, 6, 0, 0, 1, 2} target = 0 Output true Input nums[] = {2, ...

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Question 78. Maximum Product Subarray Given an array of n integers, find the maximum product obtained from a contiguous subarray of the given array. Examples Input arr[] = {-2, -3, 0, -2, -40} Output 80 Input arr[] = {5, 10, 6, -2, 1} Output 300 Input arr[] = {-1, -4, -10, 0, 70} Output 70 ...

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Question 79. Set Matrix Zeroes In the set matrix zeroes problem, we have given a (n X m) matrix, if an element is 0, set its entire row and column 0. Examples Input: { [1, 1, 1] [1, 0, 1] [1, 1, 1] } Output: { [1, 0, 1] [0, 0, 0] [1, 0, 1] ...

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Question 80. 3 Sum In 3 Sum problem, we have given an array nums of n integers, find all the unique triplets that sum up to 0. Example Input: nums = {-1, 0, 1, 2, -1, -4} Output: {-1, 0, 1}, {-1, 2, -1} Naive Approach for 3 Sum problem The Brute force approach ...

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Question 81. Find The Duplicate Number Given an array nums containing (n + 1) elements and every element is between 1 to n. If there is only one duplicate element, find the duplicate number. Examples Input: nums = {1, 3, 4, 2, 2} Output: 2 Input: nums = {3, 1, 3, 4, 2} Output: 3 Naive ...

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Question 82. Minimum Path Sum In the minimum path sum problem, we have given “a × b” matrix consisting of non-negative numbers. Your task is to find the path from top left to right bottom which minimizes the sum consisting of all the numbers which come in a path you found. Note: You can only move ...

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Question 83. Find the Duplicate Element Given an array of integers of size n+1 where each element of the array is between 1 and n (inclusive), there is one duplicate element in the array, find the duplicate element. Brute force method – Approach 1 for Find the Duplicate Element For every ith element run a loop ...

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Question 84. Next Greater Frequency Element In the next greater frequency element problem, we have given an array a[ ] of size n containing numbers. For each number in the array print, the number to it’s right in an array with a frequency greater than that of the current number. Example Input  a[] = {1, 1, ...

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Question 85. Trapping Rain Water LeetCode Solution In the Trapping Rain Water LeetCode problem, we have given N non-negative integers representing an elevation map and the width of each bar is 1. We have to find the amount of water that can be trapped in the above structure. Example Let’s understand that by an example For the ...

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Question 86. Jump Game In jump game we have given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if you are able to reach the last index. Example Input: arr = [2,3,1,1,4] ...

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Question 87. Combination Sum In combination sum problem we have given an array of positive integers arr[] and a sum s, find all unique combinations of elements in arr[] where the sum of those elements is equal to s. The same repeated number may be chosen from arr[] an unlimited number of times. Elements ...

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Question 88. Search in Sorted Rotated Array An element search in sorted rotated array can be found using binary search in O(logn) time. The objective of this post is to find a given element in a sorted rotated array in O(logn) time. Some example of a sorted rotated array is given. Example Input : arr[] = {7,8,9,10,1,2,3,5,6}; ...

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Question 89. Unique Paths A m x n 2D  grid is given and you are standing at the topmost and leftmost cell in the grid. i.e. the cell located at (1,1). Find the number of unique paths that can be taken to reach a cell located at (m,n) from the cell located at (1,1) ...

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Question 90. Maximum Subarray In the Maximum Subarray problem we have given an integer array nums, find the contiguous sub array which has the largest sum and print the maximum sum subarray value. Example Input nums[] = {-2, 1, -3, 4, -1, 2, 1, -5, 4} Output 6 Algorithm The goal is to find ...

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Question 91. Merging Intervals In merging intervals problem we have given a set of intervals of the form [l, r], merge the overlapping intervals. Examples Input {[1, 3], [2, 6], [8, 10], [15, 18]} Output {[1, 6], [8, 10], [15, 18]} Input {[1, 4], [1, 5]} Output {[1, 5]} Naive Approach for merging intervals ...

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Question 92. Peak Index in a Mountain Array What is Peak Index in a Mountain Array Problem? An array can be said as a Mountain Array if it shows the following properties: The length of the given array is should be greater than or equal to 3 LENGTH >=3. There can be only one peak or largest element ...

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Question 93. Maximum size subarray sum equals k In Maximum size subarray sum equals k we have given an array of integers and a value k. You have to find the length of the longest subarray whose sum is equal to k. If no such subarray exists then return 0. One approach is to use hashtable and check ...

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Question 94. Missing Number In Missing Number problem we have given an array of size N containing a number from 0 to N. All the values in the array are unique. We need to find the missing number which is not present in the array and that number lies between 0 to N. Here ...

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Question 95. Merge Sorted Array In merge sorted array problem we have given two sorted arrays in increasing order. In input first, we have given the number initialized to array1 and array2. These two-number are N and M. The size of array1 is equal to the sum of N and M. In array 1 first ...

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Question 96. Rotate Array Rotate array is a problem in which we have given an array of size N. We have to rotate the array in the right direction. Each element shift by one position right and last element of the array come to the first position. So, we have given a value K ...

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Question 97. Matrix Chain Multiplication using Dynamic Programming Matrix Chain Multiplication is a method in which we find out the best way to multiply the given matrices. We all know that matrix multiplication is associative(A*B = B*A) in nature. So, we have a lot of orders in which we want to perform the multiplication. Actually, in this algorithm, ...

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Question 98. Subarray Sum Equals k Given an integer array and an integer k. Find total number of contiguous subarrays of given array whose sum of elements is equal to k. Example Input 1: arr[] = {5,0,5,10,3,2,-15,4} k = 5 Output: 7 Input 2: arr[] = {1,1,1,2,4,-2} k = 2 Output: 4 Explanation : consider example-1 ...

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Question 99. Merge K Sorted Arrays and Print Sorted Output Problem Statement In the “Merge K Sorted Arrays and Print Sorted Output” problem we have given k sorted arrays of different size. Write a program to merge those arrays and prints the final sorted array as output. Input Format The first line containing an integer n. Next n lines containing ...

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Question 100. Find the Minimum Element in a Sorted and Rotated Array Problem Statement In the “Find the Minimum Element in a Sorted and Rotated Array” problem we have given a sorted array a[]. This array is rotated at some unknown point, find the minimum element in this array. Input Format The first and only one line containing an integer value n. ...

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Question 101. Stock Buy Sell to Maximize Profit Problem Statement In the “Stock Buy Sell to Maximize Profit” problem we have given an array that contains stock price on each day, find the maximum profit that you can make by buying and selling in those days. Here, we can buy and sell multiple times but only after selling ...

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Question 102. Merge Overlapping Intervals II Problem Statement In the “Merge Overlapping Intervals II” problem we have given a set of intervals. Write a program that will merge the overlapping intervals into one and print all the non-overlapping intervals. Input Format The first line containing an integer n. Second-line containing n pairs where each pair is ...

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Question 103. Maximum Subarray Sum using Divide and Conquer Problem Statement In the “Maximum Subarray Sum using Divide and Conquer” problem we have given an array of both positive and negative integers. Write a program that will find the largest sum of the contiguous subarray. Input Format The first line containing an integer N. Second-line containing an array of ...

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Question 104. Pancake Sorting Problem Problem Statement “Pancake Sorting Problem” is based on pancake sorting. Given an unsorted array, we need to write a program that uses only flip operation to sort the array. Flip is the operation that reverses the array. Input Format The first line containing an integer N. Second-line containing N space-separated ...

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Question 105. Pancake Sorting Problem Statement In the “Pancake Sorting” problem we have given an array of integers A[]. Sort the array by performing a series of pancake flips. In one pancake flip we do the following steps: Choose an integer k where 1 <= k <= arr.length. Reverse the sub-array arr[0…k-1] (0-indexed). Input ...

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Question 106. Arrange given Numbers to Form the Biggest Number II Problem Statement In the “Arrange given Numbers to Form the Biggest Number II” problem, we have given an array of positive integers.  Arrange them in such a way that the arrangement will form the largest value. Input Format The first and only one line containing an integer n. Second-line containing ...

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Question 107. Shuffle a given Array Problem Statement In the “Shuffle a given Array” problem we have given an array of integers. Write a program that shuffles the given array. That is, it will shuffle the elements in the array randomly. Input Format The first line containing an integer n. Second-line containing n space-separated integer Output ...

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Question 108. Find the Row with Maximum Number of 1’s Problem Statement In the “Find the Row with Maximum Number of 1’s” problem we have given a matrix(2D array) containing binary digits with each row sorted. Find the row which has the maximum number of 1’s. Input Format The first line containing two integers values n, m. Next, n lines ...

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Question 109. Maximum Product Subarray II Problem Statement In the “Maximum Product Subarray II” problem we have given an array consisting of positive, negative integers, and also zeroes. We need to find the maximum product of the subarray. Input Format The first line containing an integer N. Second-line containing N space-separated integers. Output Format The only ...

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Question 110. Maximum Sum Increasing Subsequence Problem Statement In the “Maximum Sum Increasing Subsequence” problem we have given an array. Find the sum of the maximum subsequence of the given array, that is the integers in the subsequence are in sorted order. A subsequence is a part of an array which is a sequence that is ...

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Question 111. Implement Two Stacks in an Array Problem Statement In the “Implement Two Stacks in an Array” problem we have to implement two stacks in an array such that, if the user wants to push an element in either of two stacks then there should not be an error till the array gets full. Example Push 5 ...

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Question 112. Number of Smaller Elements on Right Side Problem Statement In the “Number of Smaller Elements on Right Side” problem, we have given an array a[]. Find the number of smaller elements that are on the right_side of each element. Input Format The first and only one line containing an integer N. Second-line containing N space-separated integers. Output ...

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Question 113. Elements Appear more than N/K times in Array Problem Statement In the “Elements Appear more than N/K times in Array” problem we have given an integer array of size n. Find the elements which appear more than n/k times. Where k is the input value. Input Format The first and only one line containing two integers N and ...

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Question 114. Find the Peak Element from an Array Problem Statement In the “Find the Peak Element from an Array” problem we have given an input array of integers. Find a peak element. In an array, an element is a peak element, if the element is greater than both the neighbours. For corner elements, we can consider the only ...

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Question 115. Find the Maximum Repeating Number in Array Problem Statement In the “Find the Maximum Repeating Number in Array” problem we have given an unsorted array of size N. Given array contains numbers in range {0, k} where k <= N. Find the number that is coming the maximum number of times in the array. Input Format The ...

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Question 116. First Circular Tour to Visit all the Petrol Bunks In the first circular tour to visit all the petrol bunks problem the statement is such that there is a circle with n petrol pumps on the circle. Every petrol pump has a pair of data. The first value is the amount of petrol pump has and the second is ...

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Question 117. Four Elements that Sum to Given Problem Statement In four elements that sum to a given problem, we have given an array containing N elements that may be positive or negative. Find the set of four elements whose sum is equal to given value k. Input Format First-line containing an integer N. Second-line containing an array ...

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Question 118. Partition Problem Problem Statement In the Partition problem, we have given a set that contains n elements. Find whether the given set can be divided into two sets whose sum of elements in the subsets is equal. Example Input arr[] = {4, 5, 11, 9, 8, 3} Output Yes Explanation The array ...

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Question 119. The Celebrity Problem Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

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Question 120. Subarray with Given Sum Problem Statement In the subarray with the given sum problem, we have given an array containing n positive elements. We have to find the subarray in which the sum of all the elements of the subarray equal to a given_sum. Subarray is obtained from the original array by deleting some ...

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Question 121. Maximum Element in an Array which is Increasing and then Decreasing Problem Statement In the given array which contains n elements. Elements are stored in such a way that first k elements are in increasing order and then n-k elements in decreasing from there, we need to find the maximum element in the array. Example a)    Input array : [15, 25, ...

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Question 122. Find the Lost Element From a Duplicated Array Problem Statement Given two arrays A and B, one array is a duplicate of the other except one element. The one element is missing from either A or B. we need to find the lost element from a duplicated array. Example 5 1 6 4 8 9 6 4 8 ...

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Question 123. Subarray and Subsequence Problem Statement In the subarray and subsequence problem, we have to print all the subarrays and subsequences for a given array. Generate all possible non-empty subarrays. A subarray is commonly defined as a part or section of an array in which the contiguousness is based on the index. The subarray ...

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Question 124. Merge Two Sorted Arrays Problem Statement In merge two sorted arrays problem, we have given two input sorted arrays, we need to merge these two arrays such that the initial numbers after complete sorting should be in the first array and remaining in the second array. Example Input A[] = {1, 3, 5, 7, ...

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Question 125. Count of Triplets With Sum Less than Given Value Problem Statement We have given an array containing N number of elements. In the given array, Count the number of triplets with a sum less than the given value. Example Input a[] = {1, 2, 3, 4, 5, 6, 7, 8} Sum = 10 Output 7 Possible triplets are : ...

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Question 126. Next Greater Element in an Array Problem Statement Given an array, we will find the next greater element of each element in the array. If there is no next greater element for that element then we will print -1, else we will print that element. Note: Next greater element is the element that is greater and ...

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Question 127. Merging Two Sorted Arrays Problem Statement In merging two sorted arrays problem we have given two sorted arrays, one array with size m+n and the other array with size n. We will merge the n sized array into m+n sized array and print the m+n sized merged array. Example Input 6 3 M[] = ...

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Question 128. Find Element Using Binary Search in Sorted Array Problem Statement Given a sorted array, Find element using binary search in the sorted array. If present, print the index of that element else print -1. Example Input arr[] =  {1, 6, 7, 8, 9, 12, 14, 16, 26, 29, 36, 37, 156} X = 6 //element to be searched ...

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Question 129. Find Triplet in Array With a Given Sum Problem Statement Given an array of integers, find the combination of three elements in the array whose sum is equal to a given value X. Here we will print the first combination that we get. If there is no such combination then print -1. Example Input N=5, X=15 arr[] = ...

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Question 130. Find Duplicates in an Array in Most Efficient Way Problem Statement Display all the elements which are duplicates in the most efficient way in O(n) and O(1) space. Given an array of size n which contains numbers from range 0 to n-1, these numbers can occur any number of times. Find duplicates in an array in the most efficient ...

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Question 131. Sort 0s 1s and 2s in an Array Problem Statement Given an array containing N elements where elements of the array are 0,1 or 2. Sort or Segregate 0s 1s and 2s in an array. Arrange all zeros in the first half, all ones in the second half and all twos in the third half. Example Input 22 ...

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Question 132. Smallest Positive Number Missing in an Unsorted Array Problem Statement In the given unsorted array find the smallest positive number missing in an unsorted array. A positive integer doesn’t include 0. We can modify the original array if needed. The array may contain positive and negative numbers. Example a. Input array : [3, 4, -1, 0, -2, 2, 1, ...

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Question 133. Move All the Zeros to the End of the Given Array Problem Statement In the given array move all the zeros which are present in the array to the end of the array. Here there is always a way exist to insert all the number of zeroes to the end of the array. Example Input 9 9 17 0 14 0 ...

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Question 134. Count Number of Occurrences in a Sorted Array Problem Statement In the “Count Number of Occurrences in a Sorted Array” problem, we have given a sorted array. Count the number of occurrences or frequency in a sorted array of X where X is an integer. Example Input 13 1 2 2 2 2 3 3 3 4 4 ...

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Question 135. Find Smallest Missing Number in a Sorted Array Problem Statement In the “Find Smallest Missing Number in a Sorted Array” problem we have given an integer array. Find the smallest missing number in N sized sorted array having unique elements in the range of 0 to M-1, where M>N. Example Input [0, 1, 2, 3, 4, 6, 7, ...

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Question 136. First Repeating Element Problem Statement We have given an array that contains n integers. We have to find the first repeating element in the given array. If there is no repeated element then print “No repeating integer found”. Note: Repeating elements are those elements that come more than once. (Array may contain duplicates) ...

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Question 137. A Product Array Puzzle Problem Statement In a product array puzzle problem we need to construct an array where the ith element will be the product of all the elements in the given array except element at the ith position. Example Input  5 10 3 5 6 2 Output 180 600 360 300 900 ...

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Question 138. Find All Pairs With a Given Difference Problem Statement We have given an array of containing different elements or no repeated elements present in the array. Find all pairs with a given difference. If there is no any pair with given different then print “No pair with given different”. Example Input 10 20 90 70 20 80 ...

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Question 139. Find the first Repeating Number in a Given Array Problem Statement There can be multiple repeating numbers in an array but you have to find the first repeating number in a given array (occurring the second time). Example Input 12 5 4 2 8 9 7 12 5 6 12 4 7 Output 5 is the first repeating element ...

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Question 140. Majority Element Problem Statement Given a sorted array, we need to find the majority element from the sorted array. Majority element: Number occurring more than half the size of the array. Here we have given a number x we have to check it is the majority_element or not. Example Input 5 2 ...

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Question 141. Find the Missing Number Problem Statement In finding the missing number from an array of 1 to N numbers we have given an array that contains N-1 numbers. One number is missing from an array of numbers from 1 to N. We have to find the missing number. Input Format First-line containing an integer ...

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Microsoft String Questions

Question 142. Longest Common Prefix Leetcode Solution Problem Statement The Longest Common Prefix LeetCode Solution – “Longest Common Prefix” states that given an array of strings. We need to find the longest common prefix among these strings. If there doesn’t exist any prefix, return an empty string. Example: Input: strs = ["flower","flow","flight"] Output: "fl" Explanation: “fl” is the longest ...

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Question 143. Valid Palindrome II Leetcode Solution Problem Statement The Valid Palindrome II LeetCode Solution – “Valid Palindrome II” states that given the string s, we need to return true if s can be a palindrome string after deleting at most one character. Example: Input: s = "aba" Output: true Explanation: The input string is already palindrome, so there’s ...

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Question 144. Valid Parentheses Leetcode Solution Problem Statement The Valid Parentheses LeetCode Solution – “Valid Parentheses” states that you’re given a string containing just the characters '(', ')', '{', '}', '[' and ']'. We need to determine whether the input string is a valid string or not. A string is said to be a valid string if open brackets must be closed ...

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Question 145. Largest Number Leetcode Solution Problem Statement The Largest Number LeetCode Solution – “Largest Number” states that given a list of non-negative integers nums, we need to arrange the numbers in such a way that they form the largest number and return it. Since the result may be very large, so you need to return ...

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Question 146. Implement Trie (Prefix Tree) Leetcode Solution Problem Statement The Implement Trie (Prefix Tree) LeetCode Solution – “Implement Trie (Prefix Tree)” asks you to implement the Trie Data Structure that performs inserting, searching and prefix searching efficiently. Example: Input: ["Trie", "insert", "search", "search", "startsWith", "insert", "search"] [[], ["apple"], ["apple"], ["app"], ["app"], ["app"], ["app"]] Output: [null, null, true, false, true, null, true] Explanation: After inserting all the strings, trie looks like this. Word apple is searched which ...

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Question 147. Palindrome Partitioning Leetcode Solution Problem Statement The Palindrome Partitioning LeetCode Solution – “Palindrome Partitioning” states that you’re given a string, partition the input string such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of the input string. Example: Input: s = "aab" Output: [["a","a","b"],["aa","b"]] Explanation: There exist exactly 2 valid ...

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Question 148. Palindromic Substrings Leetcode Solution Problem Statement The Palindromic Substrings LeetCode Solution – “Palindromic Substrings” asks you to find a total number of palindromic substrings in the input string. A string is a palindrome when it reads the same backward as forward. A substring is a contiguous sequence of characters within the string. Example: Input: s = "aaa" Output: ...

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Question 149. Maximum Length of a Concatenated String with Unique Characters Leetcode Solution Problem Statement The Maximum Length of a Concatenated String with Unique Characters LeetCode Solution – “Maximum Length of a Concatenated String with Unique Characters” says that you’re given an array of strings and you need to choose any subsequence of the given array and concatenate those strings to form the ...

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Question 150. Shortest Word Distance Leetcode Solution Problem Statement The Shortest Word Distance LeetCode Solution – says that you’re given an array of strings and two different words. We need to return the shortest distance between these two words that appear in the input string. Example: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "coding", word2 = "practice" Output: 3 Explanation: Word “coding” occurs at position 4. ...

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Question 151. Minimum Number of Steps to Make Two Strings Anagram Leetcode Solutions Problem Statement In this problem, we are given two strings ‘s’ & ‘t’ consisting of lower-case English characters. In one operation, we can choose any character in string ‘t’ and change it to some other character. We need to find the minimum number of such operations to make ‘t’ an ...

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Question 152. Isomorphic Strings Leetcode Solution Problem Statement In this problem, we are given two strings, a and b. Our goal is to tell whether the two strings are isomorphic or not. Two strings are called isomorphic if and only if the characters in the first string can be replaced by any character(including itself) at all ...

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Question 153. Is Subsequence Leetcode Solution Problem Statement In this problem, we are given two different strings. The goal is to find out whether the first string is a subsequence of the second. Examples first string = "abc" second string = "mnagbcd" true first string = "burger" second string = "dominos" false Approach(Recursive) This is easy ...

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Question 154. Add Binary Leetcode Solution Problem Statement Given two binary strings a and b, we have to add these two strings and then return the result as a binary string. Binary string are the strings that contains only 0s and 1s. Example a = "11", b = "1" "100" a = "1010", b = "1011" "10101" Approach For adding two ...

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Question 155. Valid Palindrome Leetcode Solution Problem Statement Given a string, we have to determine if it is a palindrome, considering only alphanumeric characters i.e. numbers and alphabets only. We also have to ignore cases for alphabet characters. Example "A man, a plan, a canal: Panama" true Explanation: “AmanaplanacanalPanama”  is a valid palindrome. "race a car" ...

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Question 156. Roman to Integer Leetcode Solution In the problem “Roman to Integer”, we are given a string representing some positive integer in its Roman numeral form. Roman numerals are represented by 7 characters that can be converted to integers using the following table: Note: The integer value of the given roman numeral will not exceed or ...

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Question 157. Reformat The String Leetcode Solution Problem Statement In this problem, we are given an alphanumeric string i.e. the string has only lowercase alphabets (a-z) and digits(0-9). We are required to return any permutation of this string, in which there is no consecutive alphabet in it or no consecutive digits. If no such permutation is there, ...

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Question 158. Multiply Strings Leetcode Solution The problem Multiply Strings Leetcode solution asks us to multiply two strings which are given to us as input. We are required to print or return this result of multiplying to the caller function. So to put it more formally given two strings, find the product of the given strings. ...

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Question 159. Integer to Roman Leetcode Solution In this problem, we are given an integer and are required to convert into roman numeral. Thus the problem is generally referred to as “Integer to Roman” and this is Integer to Roman Leetcode Solution. If someone does not know about Roman numerals. In the old times, people did not ...

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Question 160. Group Anagrams We have to find out the group anagrams of the given words. This means for each word we are going to sort it and store it as a key and original input which is not sorted as a value and if any other input has the same value as a ...

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Question 161. Integer to English words In problem “Integer to English words” we have given a non-negative integer and the tasks to convert that integer into its numerical words or we get an input of a number, any number, and our task is to represent that number in a string form. Let’s see one example, the ...

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Question 162. Letter Combinations of a Phone Number In letter combinations of a phone number problem, we have given a string containing numbers from 2 to 9. The problem is to find all the possible combinations that could be represented by that number if every number has some letters assigned to it. The assignment of the number is ...

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Question 163. Longest Substring Without Repeating Characters LeetCode Solution Longest Substring Without Repeating Characters LeetCode Solution – Given a string, we have to find the length of the longest substring without repeating characters. Let’s look into a few examples: Example pwwkew 3 Explanation: Answer is “wke” with length 3 aav 2 Explanation: Answer is “av” with length 2 Approach-1 ...

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Question 164. Palindrome Permutation Problem Statement The problem “Palindrome Permutation” states that you are given a string. Check if it can be rearranged to form a palindromic string. Example superdupers yes Explanation The given input string can be rearranged to superdrepus. It is a palindromic string. So our answer to this example is yes. ...

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Question 165. Text Justification LeetCode Solution We will discuss Text Justification LeetCode Solution today Problem Statement The problem “Text Justification” states that you are given a list s[ ] of type string of size n and an integer size. Justify the text such that each line of text consists of size number of characters. You can ...

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Question 166. Queue based approach for first non-repeating character in a stream Problem Statement The problem “Queue based approach for first non-repeating character in a stream” states that you are given a stream containing lower case characters, find the first non-repeating character whenever a new character is added to the stream, and if there is no non-repeating character return -1. Examples aabcddbe ...

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Question 167. Palindrome Substring Queries Problem Statement The problem “Palindrome Substring Queries” states that you are given a String and some queries. With those queries, you have to determine if the formed substring from that query is a palindrome or not. Example String str = "aaabbabbaaa" Queries q[] = { {2, 3}, {2, 8},{5, 7}, ...

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Question 168. Palindrome Partitioning Problem Statement Given a string, find the minimum number of cuts required such that all the substrings of partitions are palindromes. Since we are cutting our original string into different partitions such that all the substrings are palindromes, we call this problem the Palindrome Partition Problem. Example  asaaaassss 2 Explanation: ...

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Question 169. Reverse words in a string Problem Statement “Reverse words in a string” states that you are given a string s of size n. Print the string in reverse order such that the last word becomes the first, second last becomes the second, and so on. Hereby string we refer to a sentence containing words instead ...

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Question 170. Mobile Numeric Keypad Problem Problem Statement In the mobile numeric keypad problem, we consider a numeric keypad.  We need to find all number of possible numeric sequences of given length such that you are only allowed to press buttons which are top, down, left, and right of the current button. You are not allowed ...

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Question 171. Decode Ways In Decode Ways problem we have given a non-empty string containing only digits, determine the total number of ways to decode it using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Example S = “123” Number of ways to decode this string is 3 If we ...

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Question 172. Edit Distance In the edit distance problem we have to find the minimum number of operations required to convert a string X of length n to another string Y of length m. Operations allowed: Insertion Deletion Substitution Example Input: String1 = “abcd” String2 = “abe” Output: Minimum operations required is 2 ( ...

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Question 173. Longest Palindromic Subsequence In the longest palindromic subsequence problem we have given a string, find the length of the longest palindromic subsequence. Examples Input: TUTORIALCUP Output: 3 Input: DYNAMICPROGRAMMING Output: 7 Naive Approach for Longest Palindromic Subsequence The naive approach to solve the above problem is to generate all the subsequences of the ...

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Question 174. KMP Algorithm KMP(Knuth-Morris-Pratt) algorithm is used for pattern searching in a given string. We are given a string S and a pattern p, our goal is to determine whether or not the given pattern is present in the string. Example Input: S = “aaaab” p = “aab” Output: true Naive Approach The ...

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Question 175. Fizz Buzz The problem name might seem fuzzy. Fizz Buzz is a game with which children are taught about the division. So, without much hassle let’s clear the buzz around it. Problem Statement Let us write a program where for multiples of 3 you print “Fizz”, for the multiples of 5 “Buzz” ...

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Question 176. Fizz Buzz Leetcode In Fizz Buzz problem we have given a number n, print the string representation of numbers from 1 to n with the given conditions: Print “Fizz” for multiples of 3. Print “Buzz” for multiples of 5. Print “FizzBuzz” for multiples of both 3 and 5. Otherwise, print the number in ...

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Question 177. Decode String Suppose, you are given an encoded string. A string is encoded in some kind of pattern, your task is to decode the string. Let us say, < no of times string occurs > [string ] Example Input 3[b]2[bc] Output bbbcaca Explanation Here “b” occurs 3times and “ca” occur 2 times. ...

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Question 178. Postfix to Infix Conversion In postfix to infix conversion problem, we have given expression in postfix notation. Write a program to convert the given notation in infix notation. Infix Notation In this notation, the operators are written between the operands. It is similar to how we generally write an expression. For instance: A + ...

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Question 179. Next Permutation In the next permutation problem we have given a word, find the lexicographically greater_permutation of it. Example input : str = "tutorialcup" output : tutorialpcu input : str = "nmhdgfecba" output : nmheabcdfg input : str = "algorithms" output : algorithsm input : str = "spoonfeed" output : Next Permutation ...

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Question 180. Longest Common Prefix using Sorting In the Longest Common Prefix using Sorting problem we have given a set of strings, find the longest common prefix. i.e. find the prefix part that is common to all the strings. Example Input1: {“tutorialcup”, “tutorial”, “tussle”, “tumble”} Output: "tu" Input2: {"baggage", "banana", "batsmen"} Output: "ba" Input3: {"abcd"} Output: "abcd" ...

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Question 181. Backspace String Compare In the backspace string compare problem we have given two Strings S and T, check if they are equal or not. Note that the strings contain ‘#’ which means backspace character. Examples Input S = “ab#c” T = “ad#c” Output true (as both S and T converts to “ac”) Input ...

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Question 182. Regular Expression Matching In the Regular Expression Matching problem we have given two strings one (let’s assume it x) consists of only lower case alphabets and second (let’s assume it y) consists of lower case alphabets with two special characters i.e, “.” and “*”. The task is to find whether the second string ...

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Question 183. Reorganize String In Reorganize String problem we have given a string containing some characters “a-z” only. Our task is to rearrange those characters such that no two same characters are adjacent to each other. Example Input apple Output pelpa Input book Output obko Input aa Output not possible Input aaab Output not ...

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Question 184. String Compression In the String Compression problem, we have given an array a[ ] of type char. Compress it as the character and count of a particular character (if the count of character is 1 then the only character is stored in a compressed array). The length of the compressed array should ...

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Question 185. Valid Parentheses LeetCode Solution In Valid Parentheses LeetCode problem we have given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid. Here we will provide a Valid Parentheses LeetCode Solution to you. An input string is valid if: Open brackets must be closed ...

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Question 186. Longest Common Prefix using Trie In the Longest Common Prefix using Trie problem we have given a set of strings, find the longest common prefix. i.e. find the prefix part that is common to all the strings. Example Input1: {“tutorialcup”, “tutorial”, “tussle”, “tumble”} Output: "tu" Input2: {"baggage", "banana", "batsmen"} Output: "ba" Input3: {"abcd"} Output: "abcd" ...

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Question 187. Count and Say Count and Say in which we have given a number N and we need to find the Nth term of the count and say sequence. Firstly we need to understand what is count and say sequence. Firstly see some terms of the sequence: 1st term is “1”. 2nd term is ...

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Question 188. Find unique character in a string In Find unique character in a string problem, we have given a string containing only lower case alphabets(a-z). We need to find the first non-repeating character in it and print the index. if no such character exists print -1. Input Format Only a single line containing string. Output Format Print ...

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Question 189. Integer to Roman Integer to Roman conversion. We have given a number N and we need to print the Roman number of N. Roman numbers are represented by the use of {I, V, X, L, C, D, M} values. Let’s see some examples for good understanding. Input Format Only a single line containing ...

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Question 190. Perform String Shifts Leetcode A shift is a process in which alphabets are incremented by 1 in their ASCII value. For the last alphabet z it starts again i.e. shift of z will be a. In perform string shifts leetcode problem we have Given a string s (lowercase characters only) and an array a[ ...

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Question 191. Check whether Strings are K Distance Apart or Not Problem Statement Given two strings and an integer k, write a program to check whether the given strings are k distance apart or not. That is if any character is mismatched or any character is to be removed then it is known as k distance apart. Input Format The first ...

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Question 192. Check length of a String is Equal to the Number Appended at its Last Problem Statement In the “Check length of a string is Equal to the Number Appended at its Last” problem we have given a string that is appended with a number at last. Write a program that checks whether the length of the string excluding the number is the same as ...

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Question 193. Check if all Rows of a Matrix are Circular Rotations of Each Other Problem Statement In the “Check if all Rows of a Matrix are Circular Rotations of Each Other” problem we have given a char matrix, write a program to find whether all rows are circular rotations of each other or not. If all rows are circular rotations of each other print ...

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Question 194. Sort a String According to Another String Problem Statement Given two input strings, a pattern and a string. We need to sort the string according to the order defined by the pattern. Pattern string has no duplicates and it has all characters of the string. Input Format The first line containing a string s which we need ...

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Question 195. Check if String Follows Order of Characters by a Pattern or not Problem Statement In the “Check if String Follows Order of Characters by a Pattern or not” problem we have to check if characters in the given input string follow the same order as determined by characters present in the given input pattern then print “Yes” else print “No”. Input Format ...

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Question 196. Reverse String Without Temporary Variable Problem Statement In the “Reverse String Without Temporary Variable” problem we have given a string “s”. Write a program to reverse this string without using any extra variable or space. Input Format The first line containing the given string “s”. Output Format Print the string which is reverse of the ...

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Question 197. Minimum Characters to be Added at Front to Make String Palindrome Problem Statement In the “Minimum Characters to be Added at Front to Make String Palindrome” problem we have given a string “s”. Write a program to find the minimum characters to be added at the front to make a string palindrome. Input Format The first and only one line containing ...

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Question 198. Kth Non-repeating Character Problem Statement In the “Kth Non-repeating Character” we have given a string “s”. Write a program to find out the kth non-repeating_character. If there are less than k character which is non-repeating in the string then print “-1”. Input Format The first and only one line containing a string “s”. ...

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Question 199. Generate all Binary Strings from Given Pattern Problem Statement In the “Generate all Binary Strings from Given Pattern” problem we have given input string “s” consists of 0, 1, and ? (wildcard char). We need to generate all possible binary strings by replacing ? with ‘0’ and ‘1’. Input Format The first and only one line containing ...

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Question 200. Longest Common Prefix Word by Word Matching Problem Statement In the “Longest Common Prefix using Word by Word Matching” problem, we have given N strings.  Write a program to find the longest common prefix of the given strings. Input Format The first line containing an integer value N which denotes the number of strings. Next N lines ...

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Question 201. Longest Common Prefix using Character by Character Matching Problem Statement In the “Longest Common Prefix using Character by Character Matching” problem we have given an integer value N and N strings. Write a program to find the longest common prefix of the given strings. Input Format The first line containing an integer value N which denotes the number ...

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Question 202. Permutations of a Given String Using STL Problem Statement In the “Permutations of a Given String Using STL” problem, we have given a string “s”. Print all the permutations of the input string using STL functions. Input Format The first and only one line containing a string “s”. Output Format Print all the permutation of the given ...

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Question 203. Longest Common Prefix Using Binary Search II Problem Statement In the “Longest Common Prefix Using Binary Search II” problem we have given an integer value N and N strings. Write a program that will print the longest common prefix of given strings. If there is no common prefix then print “-1”. Input Format The first line containing ...

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Question 204. Length of Longest valid Substring Problem Statement In the “Length of Longest valid Substring” we have given a string that contains the opening and closing parenthesis only. Write a program that will find the longest valid parenthesis substring. Input Format The first and only one line containing a string s. Output Format The first and ...

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Question 205. Arrange given Numbers to Form the Biggest Number II Problem Statement In the “Arrange given Numbers to Form the Biggest Number II” problem, we have given an array of positive integers.  Arrange them in such a way that the arrangement will form the largest value. Input Format The first and only one line containing an integer n. Second-line containing ...

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Question 206. Check if a Linked list of Strings form a Palindrome Problem Statement In the “Check if a Linked list of Strings form a Palindrome” problem we have given a linked list handling string data. Write a program to check whether the data forms a palindrom or not. Example ba->c->d->ca->b 1 Explanation: In the above example we can see that the ...

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Microsoft Tree Questions

Question 207. Populating Next Right Pointers in Each Node Leetcode Solution Problem Statement The Populating Next Right Pointers in Each Node LeetCode Solution – “Populating Next Right Pointers in Each Node” states that given the root of the perfect binary tree and we need to populate each next pointer of the node to its next right node. If there is no next ...

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Question 208. Delete Nodes and Return Forest Leetcode Solution Problem Statement The Delete Nodes and Return Forest LeetCode Solution – “Delete Nodes and Return Forest” states that given the root of the binary tree where each node has a distinct value. We’re also given an array,  to_delete, where we need to delete all the nodes with values contained in ...

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Question 209. Recover Binary Search Tree Leetcode Solution Problem Statement The Recover Binary Search Tree LeetCode Solution – “Recover Binary Search Tree” states that given the root of the binary search tree, where the values of exactly two nodes are swapped by mistake. We need to recover the tree without changing its structure. Example: Input: root = [1,3,null,null,2] Output: [3,1,null,null,2] ...

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Question 210. Symmetric Tree Leetcode Solution Problem Statement The Symmetric Tree LeetCode Solution – “Symmetric Tree” states that given the root of the binary tree and we need to check if the given binary tree is a mirror of itself (symmetric around its center) or not? If Yes, we need to return true otherwise, false. Example: ...

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Question 211. Root to Leaf path with target sum Leetcode Solutions A binary tree and an integer K are given. Our goal is to return whether there is a root-to-leaf path in the tree such that it’s sum is equal to the target-K. The sum of a path is the sum of all nodes that lie on it. 2 / \ ...

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Question 212. Queries for Number of Distinct Elements in a Subarray We have given an array of integer and a number of queries and we have to find out the number of all the distinct elements we have within the given range, the query consists of two numbers left and right, this is the given range, with this given range we ...

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Question 213. Morris Traversal Morris traversal is a method to traverse the nodes in a binary tree without using stack and recursion. Thus reducing the space complexity to linear. Inorder Traversal Example 9 7 1 6 4 5 3 1           /    \         2    ...

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Question 214. Construct Binary Tree from given Parent Array representation The problem “Construct Binary Tree from given Parent Array representation” states that you are given an array. This input array represents a binary tree. Now you need to construct a binary tree on the basis of this input array. The array stores the index of parent node at each index. ...

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Question 215. Given a binary tree, how do you remove all the half nodes? The problem “Given a binary tree, how do you remove all the half nodes?” states that you are given a binary tree. Now you need to remove the half nodes. A half node is defined as a node in the tree that has only a single child. Either it is ...

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Question 216. Iterative Preorder Traversal The problem “Iterative Preorder Traversal” states that you are given a binary tree and now you need to find the preorder traversal of the tree. We are required to find the preorder traversal using iterative method and not the recursive approach. Example   5 7 9 6 1 4 3 ...

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Question 217. Write Code to Determine if Two Trees are Identical The problem “Write Code to Determine if Two Trees are Identical” states that you are given two binary trees. find out if they are identical or not? Here, identical tree means that both the binary trees have the same node value with the same arrangement of nodes. Example Both trees ...

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Question 218. Boundary Traversal of binary tree Problem Statement The problem “Boundary Traversal of binary tree” states that you are given a binary tree. Now you need to print the boundary view of a binary tree. Here boundary traversal means that all the nodes are shown as the boundary of the tree. The nodes are seen from ...

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Question 219. Clone a Binary Tree with Random Pointers Problem Statement You are given a complete binary tree with some random pointers. Random pointers are referred to nodes which every node points to other than its left and right child. So, this also changes the standard structure of a node in a simple binary tree. Now the node of ...

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Question 220. Level order traversal using two Queues Problem Statement The problem “Level order traversal using two Queues” states that you are given a binary tree, print its level order traversal line by line. Examples Input 5 11 42 7 9 8 12 23 52 3 Input 1 2 3 4 5 6 Algorithm for Level Order Traversal ...

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Question 221. Convert BST into a Min-Heap without using array Problem Statement “Convert BST into a Min-Heap without using array” problem states that you are given a BST (binary search tree) and you need to convert it into a min-heap. The min-heap should contain all the elements in the binary search tree. The algorithm should run in linear time complexity. ...

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Question 222. Merge two BSTs with limited extra space Problem Statement The problem “Merge two BSTs with limited extra space” states that you are given two binary search tree(BST) and you need to print the elements from both the trees in sorted order. That is in such an order that it seems that elements are from a single BST. ...

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Question 223. Binary Tree to Binary Search Tree Conversion using STL set Problem Statement We are given a binary tree and we need to convert it into a binary search tree. The problem “Binary Tree to Binary Search Tree Conversion using STL set” asks to do conversion using STL set. We have already discussed converting the binary tree into BST but we ...

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Question 224. K’th Largest element in BST using constant extra space Problem Statement “K’th Largest element in BST using constant extra space” states that you are given a binary search tree and you need to find the kth largest element in it. So if we arrange the elements of the binary search tree in descending order then we need to return ...

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Question 225. Vertical sum in a given binary tree Problem Statement “Vertical sum in a given binary tree” problem states that you are given a binary tree and we need to find the sum of each vertical level. By vertical level, we mean if we draw vertical lines at a distance of 1 unit in the left and right ...

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Question 226. A program to check if a binary tree is BST or not Problem Statement “A program to check if a binary tree is BST or not” states that you are given a binary tree and you need to check if the binary tree satisfies the properties of the binary search tree. So, the binary tree has the following properties:  The left subtree ...

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Question 227. Merge Two Balanced Binary Search Trees Problem Statement Given Two Balanced Binary Search Trees, there are n elements in the first BST and m elements in the second BST. Write an algorithm to merge two balanced binary search trees to form a third balanced Binary Search Tree with (n + m) elements. Example Input Output Pre-order ...

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Question 228. Binary Search Tree Search and Insertion Problem Statement Write an algorithm to perform searching and insertion in Binary Search Tree. So what we are going to do is insert some of the elements from input into a binary search tree. Whenever asked to search a particular element, we’ll be searching it among the elements in BST(short ...

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Question 229. Check given array of size n can represent BST of n levels or not Problem Statement Given an array with n elements, check given array of size n can represent BST of n levels or not. That is to check whether the binary search tree constructed using these n elements can represent a BST of n levels. Examples arr[] = {10, 8, 6, 9, ...

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Question 230. Binary Tree to Binary Search Tree Conversion In binary tree to binary search tree conversion problem, we have given a binary tree convert it to Binary Search Tree without changing the structure of the tree. Example Input Output pre-order : 13 8 6 47 25 51 Algorithm We do not have to change the structure of the ...

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Question 231. Sorted Array to Balanced BST In sorted array to balanced BST problem, we have given an array in sorted order, construct a Balanced Binary Search Tree from the sorted array. Examples Input arr[] = {1, 2, 3, 4, 5} Output Pre-order : 3 2 1 5 4 Input arr[] = {7, 11, 13, 20, 22, ...

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Question 232. Construct BST from its given Level Order Traversal Given the level order traversal of a Binary Search Tree, write an algorithm to construct the Binary Search Tree or BST from ITS given level order traversal. Example Input levelOrder[] = {18, 12, 20, 8, 15, 25, 5, 9, 22, 31} Output In-order : 5 8 9 12 15 18 ...

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Question 233. BST to a Tree with Sum of all Smaller Keys In this problem we have given a Binary Search Tree, write an algorithm to convert best to a tree with sum of all smaller keys. Example Input Output Pre-order : 19 7 1 54 34 88 Naive Approach Traverse all the nodes one by one in any traversal form, and ...

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Question 234. Find the node with minimum value in a Binary Search Tree Given a Binary Search Tree, write an algorithm to find the node with the minimum value in a given binary search tree. Example Input Output 5 Naive Approach A simple approach is to do a tree traversal and find the node with the minimum value among all the nodes. This ...

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Question 235. Construct Binary Tree from Given Inorder and Preorder Traversals In this problem, we have inorder and preorder of the binary tree. We need to construct a binary tree from the given Inorder and Preorder traversals. Example Input: Inorder= [D, B, E, A, F, C] Preorder= [A, B, D, E, C, F] Output: Pre-order traversal of the tree formed by ...

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Question 236. Reverse a Path in BST using Queue In reverse a path in BST using queue problem we have given a Binary Search Tree and node, write an algorithm to reverse the path from root to the given node. Assume that the node exists in the BST. Example Input Target Node = 12 Output In-order traversal before the ...

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Question 237. Level order Traversal in Spiral Form In this problem we have given a binary tree,  print its level order traversal in a spiral form. Examples Input Output 10 30 20 40 50 80 70 60 Naive Approach for Level order Traversal in Spiral Form The idea is to do a normal level order traversal using a ...

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Question 238. Balanced Binary Tree In the balanced binary tree problem, we have given the root of a binary tree. We have to determine whether or not it is height balance. Examples Input Output true Input Output: false Balanced Binary Tree Every node in a balanced binary tree has a difference of 1 or less ...

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Question 239. Lowest Common Ancestor Given the root of a binary tree and two nodes n1 and n2, find the LCA(Lowest Common Ancestor) of the nodes. Example What is Lowest Common Ancestor(LCA)? The ancestors of a node n are the nodes present in the path between root and node. Consider the binary tree shown in ...

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Question 240. Segment Tree If we have performing addition on a given range of array whose element values updated any time. Then in that type of problem, we handle using a segment tree structure. Given an array a[] with n elements and you have to answer multiple queries, each of the queries is one ...

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Question 241. Binary Search Tree A binary search tree is a Binary tree with some rules that allows us to maintain the data in a sorted fashion. As it is a binary tree hence, a node can have at max 2 children. Structure of a Binary Search Tree node   Rules for Binary tree to ...

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Question 242. Maximum Binary Tree In this problem, we have given an array a[ ] of size n. Create the maximum binary tree from the array and return its root node. It is made from the array using the following steps : The root node of the tree should be the maximum value in the given ...

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Question 243. Binary Tree zigzag level order Traversal Given a binary tree, print the zigzag level order traversal of its node values. (ie, from left to right, then right to left for the next level and alternate between). Example consider the binary tree given below Below is the zigzag level order traversal of the above binary tree Types ...

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Question 244. Recover Binary Search Tree Consider a binary search tree, two nodes of the tree have been swapped, design an algorithm to recover the binary search Tree. Example Consider the binary search tree given below whose two nodes have been swapped as input. Incorrect nodes on the BST are detected(highlighted) and then swapped to obtain ...

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Question 245. Populating Next Right Pointers in Each Node Given a Binary Tree, connect nodes that are at the same level from left to right. Structure of the Tree Node: A node of the tree contains 4 components which are data(integer value), pointers(next, left and right) of the tree node type. next pointer of a node point towards its ...

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Question 246. Level of Each node in a Tree from source node Given a tree (an acyclic fully connected graph where constituent nodes are connected by bidirectional edges) and a source node. find the level of each node in a tree form source node. It is given that level of a node v with respect to the source is the distance between ...

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Question 247. Longest Common Prefix using Trie In the Longest Common Prefix using Trie problem we have given a set of strings, find the longest common prefix. i.e. find the prefix part that is common to all the strings. Example Input1: {“tutorialcup”, “tutorial”, “tussle”, “tumble”} Output: "tu" Input2: {"baggage", "banana", "batsmen"} Output: "ba" Input3: {"abcd"} Output: "abcd" ...

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Question 248. Validate Binary Search Tree Problem In Validate Binary Search Tree problem we have given the root of a tree, we have to check if it is a binary search tree or not. Example : Output: true Explanation: The given tree is a binary search tree because all elements which are left to each subtree ...

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Question 249. Path Sum What is Path Sum Problem? In the Path Sum problem, we have given a binary tree and an integer SUM. We have to find if any path from the root to leaf has a sum equal to the SUM. Path sum is defined as the sum of all the nodes ...

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Question 250. Level Order Traversal of Binary Tree Level Order Traversal of a given binary tree is the same as the BFS of the binary tree. Do we already know about what actually BFS is? if not then don’t need to feel bad just read the whole article and visit our previous articles for better understanding. BFS is a ...

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Question 251. Deletion in a Binary Tree Do we already know about what actually Binary Tree is? Now in this post, we are focusing on how to delete a node whose value is given. We are sure that the value of the node which we want to delete is always present before deletion in BT. In Binary ...

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Microsoft Graph Questions

Question 252. Find the smallest binary digit multiple of given number Problem Statement The problem “Find the smallest binary digit multiple of given number” states that you are given a decimal number N. So find the smallest multiple of N that contains only the binary digits ‘0’ and ‘1’. Example 37 111 A detailed explanation can be found below in the ...

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Question 253. Transpose Graph Problem Statement The problem “Transpose graph” states that you are given a graph and you need to find the transpose of the given graph. Transpose: Transpose of a directed graph produces another graph with same edge & node configurations but the direction of all the edges have been reversed. Example ...

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Question 254. BFS for Disconnected Graph Problem Statement The problem “BFS for Disconnected Graph” states that you are given a disconnected directed graph, print the BFS traversal of the graph. Example The BFS traversal of the graph above gives: 0 1 2 5 3 4 6 Approach Breadth first Search (BFS) traversal for Disconnected Directed Graph ...

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Question 255. Evaluate Division In evaluate division problem we have given some equations, in the form, A/B = k, where A and B are strings and k is a real number. Answer some queries, if the answer does not exist return -1. Example Input: equations: a/b = 2.0 and b/c = 3.0 queries: a/c ...

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Question 256. Graph Cloning What is Graph Cloning? Today we have with us a reference to an undirected graph. What do we have to do? Returning a deep copy of the provided graph. Let us look at the structure: The Class Node: It consists of the data value and the neighbors associated with each ...

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Question 257. Topological Sorting Given a directed acyclic graph, topologically sort the graph nodes. Topological Sorting Example Topological sorting of above graph is -> {1,2,3,0,5,4} Theory Topological Sorting is done for a Directed Acyclic Graph (DAG). A DAG has no cycles in it. ie, there is no such path starting from any node of ...

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Microsoft Stack Questions

Question 258. Trapping Rain Water Leetcode Solution Problem Statement The Trapping Rain Water LeetCode Solution – “Trapping Rain Water” states that given an array of heights which represents an elevation map where the width of each bar is 1. We need to find the amount of water trapped after rain. Example: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: Check ...

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Question 259. Valid Parentheses Leetcode Solution Problem Statement The Valid Parentheses LeetCode Solution – “Valid Parentheses” states that you’re given a string containing just the characters '(', ')', '{', '}', '[' and ']'. We need to determine whether the input string is a valid string or not. A string is said to be a valid string if open brackets must be closed ...

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Question 260. Maximum Frequency Stack Leetcode Solution Problem Statement The Maximum Frequency Stack LeetCode Solution – “Maximum Frequency Stack” asks you to design a frequency stack in which whenever we pop an element from the stack, it should return the most frequent element present in the stack. Implement the FreqStack class: FreqStack() constructs an empty frequency stack. void push(int val) pushes ...

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Question 261. Design a Stack With Increment Operation Leetcode Solution Problem Statement The Design a Stack With Increment Operation Leetcode Solution –  states that we need to design a stack that supports the below operations efficiently. Assign the maximum capacity of the stack. Perform the push operation efficiently, if the size of the stack is strictly less than the maximum capacity of ...

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Question 262. Min Stack Leetcode Solution Problem Statement Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) — Push element x onto stack. pop() — Removes the element on top of the stack. top() — Get the top element. getMin() — Retrieve the minimum element in the stack. ...

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Question 263. Design a stack that supports getMin() in O(1) time and O(1) extra space Design a stack that supports getMin() in O(1) time and O(1) extra space. Thus the special stack data structure must support all the operations of the stack like – void push() int pop() bool isFull() bool isEmpty() in constant time. Add an additional operation getMin() to return the minimum value ...

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Question 264. Implement a stack using single queue Problem Statement The problem “Implement a stack using single queue” asks us to implement a stack (LIFO) data structure using a queue (FIFO) data structure. Here LIFO means Last In First Out while FIFO means First In First Out. Example push(10) push(20) top() pop() push(30) pop() top() Top : 20 ...

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Question 265. Level order Traversal in Spiral Form In this problem we have given a binary tree,  print its level order traversal in a spiral form. Examples Input Output 10 30 20 40 50 80 70 60 Naive Approach for Level order Traversal in Spiral Form The idea is to do a normal level order traversal using a ...

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Question 266. Min Stack In min stack problem we have to design a stack to implement the following functions efficiently, push(x) –> Push an element x to the stack pop() –> Removes the item on top of stack top() –> Return the element at top of stack getMin() –> Return the minimum element present ...

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Question 267. Queue using Stacks In queue using a stack problem, we have to implement the following functions of a queue using the standard functions of stack data structure, Enqueue: Add an element to the end of the queue Dequeue: Remove an element from the start of the queue Example Input: Enqueue(5) Enqueue(11) Enqueue(39) Dequeue()  ...

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Question 268. Next Greater Frequency Element In the next greater frequency element problem, we have given an array a[ ] of size n containing numbers. For each number in the array print, the number to it’s right in an array with a frequency greater than that of the current number. Example Input  a[] = {1, 1, ...

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Question 269. Trapping Rain Water LeetCode Solution In the Trapping Rain Water LeetCode problem, we have given N non-negative integers representing an elevation map and the width of each bar is 1. We have to find the amount of water that can be trapped in the above structure. Example Let’s understand that by an example For the ...

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Question 270. Decode String Suppose, you are given an encoded string. A string is encoded in some kind of pattern, your task is to decode the string. Let us say, < no of times string occurs > [string ] Example Input 3[b]2[bc] Output bbbcaca Explanation Here “b” occurs 3times and “ca” occur 2 times. ...

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Question 271. Postfix to Infix Conversion In postfix to infix conversion problem, we have given expression in postfix notation. Write a program to convert the given notation in infix notation. Infix Notation In this notation, the operators are written between the operands. It is similar to how we generally write an expression. For instance: A + ...

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Question 272. Binary Tree zigzag level order Traversal Given a binary tree, print the zigzag level order traversal of its node values. (ie, from left to right, then right to left for the next level and alternate between). Example consider the binary tree given below Below is the zigzag level order traversal of the above binary tree Types ...

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Question 273. Backspace String Compare In the backspace string compare problem we have given two Strings S and T, check if they are equal or not. Note that the strings contain ‘#’ which means backspace character. Examples Input S = “ab#c” T = “ad#c” Output true (as both S and T converts to “ac”) Input ...

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Question 274. Implement Two Stacks in an Array Problem Statement In the “Implement Two Stacks in an Array” problem we have to implement two stacks in an array such that, if the user wants to push an element in either of two stacks then there should not be an error till the array gets full. Example Push 5 ...

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Question 275. The Celebrity Problem Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

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Question 276. Next Greater Element in an Array Problem Statement Given an array, we will find the next greater element of each element in the array. If there is no next greater element for that element then we will print -1, else we will print that element. Note: Next greater element is the element that is greater and ...

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Microsoft Queue Questions

Question 277. Moving Average from Data Stream Leetcode Solution Problem Statement The Moving Average from Data Stream LeetCode Solution – “Moving Average from Data Stream” states that given a stream of integers and a window size k. We need to calculate the moving average of all the integers in the sliding window. If the number of elements in the ...

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Question 278. Level order traversal using two Queues Problem Statement The problem “Level order traversal using two Queues” states that you are given a binary tree, print its level order traversal line by line. Examples Input 5 11 42 7 9 8 12 23 52 3 Input 1 2 3 4 5 6 Algorithm for Level Order Traversal ...

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Question 279. Implement a stack using single queue Problem Statement The problem “Implement a stack using single queue” asks us to implement a stack (LIFO) data structure using a queue (FIFO) data structure. Here LIFO means Last In First Out while FIFO means First In First Out. Example push(10) push(20) top() pop() push(30) pop() top() Top : 20 ...

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Question 280. Find the First Circular Tour that visits all the Petrol Pumps Problem Statement The problem “Find the First Circular Tour that visits all the Petrol Pumps” states that there are N petrol pumps on a circular road. Given the petrol that every petrol pump has and the amount of petrol required to cover the distance between two petrol pumps. So you ...

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Question 281. Queue based approach for first non-repeating character in a stream Problem Statement The problem “Queue based approach for first non-repeating character in a stream” states that you are given a stream containing lower case characters, find the first non-repeating character whenever a new character is added to the stream, and if there is no non-repeating character return -1. Examples aabcddbe ...

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Question 282. Implementation of Deque using circular array Problem Statement “Implementation of Deque using circular array” asks to implement the following functions of a Deque(Doubly Ended Queue) using circular array, insertFront(x) : insert an element x at the front of Deque insertRear(x) : insert an element x at the rear of Deque deleteFront() : delete an element from ...

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Question 283. Find the node with minimum value in a Binary Search Tree Given a Binary Search Tree, write an algorithm to find the node with the minimum value in a given binary search tree. Example Input Output 5 Naive Approach A simple approach is to do a tree traversal and find the node with the minimum value among all the nodes. This ...

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Question 284. Reverse a Path in BST using Queue In reverse a path in BST using queue problem we have given a Binary Search Tree and node, write an algorithm to reverse the path from root to the given node. Assume that the node exists in the BST. Example Input Target Node = 12 Output In-order traversal before the ...

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Question 285. Queue using Stacks In queue using a stack problem, we have to implement the following functions of a queue using the standard functions of stack data structure, Enqueue: Add an element to the end of the queue Dequeue: Remove an element from the start of the queue Example Input: Enqueue(5) Enqueue(11) Enqueue(39) Dequeue()  ...

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Question 286. Priority Queue in C++ FIFO manner is used to implement a queue. In a queue, insertions are done at one end (rear) and deletion takes place at another end (front). Basically, the element enters first is deleted first. We implement a priority queue using c++ inbuilt functions. Characteristics of Priority Queue A priority queue ...

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Question 287. Priority Queue A priority queue is a type of data structure which is similar to a regular queue but has a priority associated with each of its element. Higher the priority earlier the element will be served. In some cases, there are two elements with the same priority then, the element enqueued ...

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Question 288. Binary Tree zigzag level order Traversal Given a binary tree, print the zigzag level order traversal of its node values. (ie, from left to right, then right to left for the next level and alternate between). Example consider the binary tree given below Below is the zigzag level order traversal of the above binary tree Types ...

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Question 289. Level Order Traversal of Binary Tree Level Order Traversal of a given binary tree is the same as the BFS of the binary tree. Do we already know about what actually BFS is? if not then don’t need to feel bad just read the whole article and visit our previous articles for better understanding. BFS is a ...

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Microsoft Matrix Questions

Question 290. Unique Paths II Leetcode Solution Problem Statement The Unique Paths II LeetCode Solution – “Unique Paths II” states that given the m x n grid where a robot starts from the top left corner of the grid. We need to find the total number of ways to reach the bottom right corner of the grid. ...

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Question 291. Search a 2D Matrix II Leetcode Solution Problem Statement The Search a 2D Matrix II LeetCode Solution – “Search a 2D Matrix II”asks you to find an efficient algorithm that searches for a value target in an m x n integer matrix matrix. Integers in each row, as well as column, are sorted in ascending order. Example: Input: matrix = [[1,4,7,11,15],[2,5,8,12,19],[3,6,9,16,22],[10,13,14,17,24],[18,21,23,26,30]], target = 5 Output: true ...

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Question 292. Set Matrix Zeroes Leetcode Solution Problem Statement The Set Matrix Zeroes LeetCode Solution – “Set Matrix Zeroes” states that you’re given an m x n integer matrix matrix.We need to modify the input matrix such that if any cell contains the element  0, then set its entire row and column to 0‘s. You must do it in ...

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Question 293. Word Search Leetcode Solution Problem Statement Given an m x n board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cells, where “adjacent” cells are horizontally or vertically neighbouring. The same letter cell may not be used more than once. Example ...

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Question 294. Gold Mine Problem Problem Statement The “Gold Mine problem” states that you are given a 2D grid having some non-negative coins placed in each cell of the given grid. Initially, the miner is standing at the first column but there is no restriction on the row. He can start in any row. The ...

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Question 295. Minimum time required to rot all oranges Problem Statement The problem “Minimum time required to rot all oranges” states that you are given a 2D array, every cell has one of the three possible values 0, 1 or 2. 0 means an empty cell. 1 means a fresh orange. 2 means a rotten orange. If a rotten ...

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Question 296. Mobile Numeric Keypad Problem Problem Statement In the mobile numeric keypad problem, we consider a numeric keypad.  We need to find all number of possible numeric sequences of given length such that you are only allowed to press buttons which are top, down, left, and right of the current button. You are not allowed ...

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Question 297. Largest rectangular sub-matrix whose sum is 0 Problem Statement Find the maximum size sub-matrix in a 2D array whose sum is zero. A sub-matrix is nothing but a 2D array inside of the given 2D array. So, you have a matrix of signed integers, you need to calculate the sum of sub-matrices and find the matrix with ...

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Question 298. Matrix Chain Multiplication In the matrix chain multiplication II problem, we have given the dimensions of matrices, find the order of their multiplication such that the number of operations involved in multiplication of all the matrices is minimized. Consider you have 3 matrices A, B, C of sizes a x b, b x ...

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Question 299. Set Matrix Zeroes In the set matrix zeroes problem, we have given a (n X m) matrix, if an element is 0, set its entire row and column 0. Examples Input: { [1, 1, 1] [1, 0, 1] [1, 1, 1] } Output: { [1, 0, 1] [0, 0, 0] [1, 0, 1] ...

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Question 300. Unique Paths A m x n 2D  grid is given and you are standing at the topmost and leftmost cell in the grid. i.e. the cell located at (1,1). Find the number of unique paths that can be taken to reach a cell located at (m,n) from the cell located at (1,1) ...

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Question 301. Matrix Chain Multiplication using Dynamic Programming Matrix Chain Multiplication is a method in which we find out the best way to multiply the given matrices. We all know that matrix multiplication is associative(A*B = B*A) in nature. So, we have a lot of orders in which we want to perform the multiplication. Actually, in this algorithm, ...

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Question 302. Check whether Strings are K Distance Apart or Not Problem Statement Given two strings and an integer k, write a program to check whether the given strings are k distance apart or not. That is if any character is mismatched or any character is to be removed then it is known as k distance apart. Input Format The first ...

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Question 303. Check if all Rows of a Matrix are Circular Rotations of Each Other Problem Statement In the “Check if all Rows of a Matrix are Circular Rotations of Each Other” problem we have given a char matrix, write a program to find whether all rows are circular rotations of each other or not. If all rows are circular rotations of each other print ...

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Question 304. Find the Row with Maximum Number of 1’s Problem Statement In the “Find the Row with Maximum Number of 1’s” problem we have given a matrix(2D array) containing binary digits with each row sorted. Find the row which has the maximum number of 1’s. Input Format The first line containing two integers values n, m. Next, n lines ...

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Question 305. The Celebrity Problem Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

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Microsoft Other Questions

Question 306. Range Sum Query 2D – Immutable Leetcode Solution Problem Statement Range Sum Query 2D – Immutable Leetcode Solution – Given a 2D matrix matrix, handle multiple queries of the following type: Calculate the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2). Implement the NumMatrix class: NumMatrix(int[][] matrix) Initializes the object with the integer ...

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Question 307. Partition Labels LeetCode Solution Problem Statement Partition Labels LeetCode Solution – You are given a string s. We want to partition the string into as many parts as possible so that each letter appears in at most one part. Note that the partition is done so that after concatenating all the parts in order, the ...

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Question 308. Fibonacci Number LeetCode Solution Problem Statement Fibonacci Number LeetCode Solution – “Fibonacci Number” states that The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is, F(0) = 0, F(1) = 1 F(n) = F(n - 1) + F(n ...

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Question 309. Diagonal Traversal LeetCode Solution Problem Statement Diagonal Traversal LeetCode Solution – Given a 2D integer array nums, return all elements of nums in diagonal order as shown in the below images. Input: nums = [[1,2,3],[4,5,6],[7,8,9]] Output: [1,4,2,7,5,3,8,6,9] Explanation for Diagonal Traversal LeetCode Solution Key Idea The first row and the last column in this problem would serve ...

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Question 310. Valid Tic-Tac-Toe State LeetCode Solution Problem Statement Valid Tic-Tac-Toe State LeetCode Solution – We are given a Tic-Tac-Toe board as a string array board & are asked to return true iff it is possible to reach this board position during the course of a valid tic-tac-toe game. The board is a 3 x 3 array ...

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Question 311. Reverse Words in a String III LeetCode Solution Problem Statement Reverse Words in a String III LeetCode Solution – We are given a string and are asked to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Examples & Explanations Example 1: Input: s = "Let's take LeetCode ...

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Question 312. Count Submatrices With All Ones LeetCode Solution Problem Statement Count Submatrices With All Ones LeetCode Solution – We are given an m x n binary matrix and are asked to return the number of submatrices that have all ones. Examples and Explanations Example 1: Input: mat = [[1,0,1],[1,1,0],[1,1,0]] Output: 13 Explanation: There are 6 rectangles of side ...

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Question 313. Remove Duplicates from Sorted List LeetCode Solution Problem Statement Remove Duplicates from Sorted List LeetCode Solution – We are given the head of a sorted linked list. We are asked to delete all the duplicates such that each element appears only once and return the linked list sorted as well. Examples & Explanations Example 1: Input: head ...

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Question 314. Clone Graph LeetCode Solution Problem Statement Clone Graph LeetCode Solution – We are given a reference of a node in a connected undirected graph and are asked to return a deep copy of the graph. A deep copy is basically a clone where no node present in the deep copy should have the reference ...

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Question 315. Minimum Height Trees LeetCode Solution Problem Statement Minimum Height Trees LeetCode Solution – We are given a tree of n nodes labelled from 0 to n-1 as a 2D array “edges” where edge[i] = [a_i, b_i] indicates that there is an undirected edge between the two nodes a_i and b_i in the tree. We have ...

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Question 316. Kth Smallest Element in a Sorted Matrix LeetCode Solution Problem Statement Kth Smallest Element in a Sorted Matrix LeetCode Solution – We are given a matrix of size n where each of the rows and columns is sorted in ascending order. We are asked to return the kth smallest element in the matrix. Note that it is the kth ...

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Question 317. Number of Islands II LeetCode Solution Problem Statement Number of Islands II LeetCode Solution – You are given an empty 2D binary grid grid of size m x n. The grid represents a map where 0‘s represent water and 1‘s represent land. Initially, all the cells  grid are water cells (i.e., all the cells are 0‘s). We may perform an add land ...

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Question 318. Number of Dice Rolls With Target Sum LeetCode Solution Problem Statement Number of Dice Rolls With Target Sum LeetCode Solution – You have n dice and each die has k faces numbered from 1 to k. Given three integers n, k, and target, return the number of possible ways (out of the kn total ways) to roll the dice so the sum of the face-up numbers equals target. Since the answer may be ...

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Question 319. Race Car LeetCode Solution Problem Statement Race Car LeetCode Solution – Your car starts at the position 0 and speed +1 on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a sequence of instructions 'A' (accelerate) and 'R' (reverse): When you get an instruction 'A', your car does the following: position += speed ...

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Question 320. Remove Duplicates from Sorted List II LeetCode Solution Problem Statement Remove Duplicates from Sorted List II LeetCode Solution – Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well. Input: head = [1,2,3,3,4,4,5] Output: [1,2,5] Explanation The idea here is to traverse ...

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Question 321. Shortest Path in a Grid with Obstacles Elimination LeetCode Solution Problem Statement Shortest Path in a Grid with Obstacles Elimination LeetCode Solution – You are given an m x n integer matrix grid where each cell is either 0 (empty) or 1 (obstacle). You can move up, down, left, or right from and to an empty cell in one step. Return the minimum number of steps to walk from the upper left ...

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Question 322. Can Place Flowers LeetCode Solution Problem Statement Can Place Flowers LeetCode Solution – You have a long flowerbed in which some of the plots are planted, and some are not. However, flowers cannot be planted in adjacent plots. Given an integer array flowerbed containing 0‘s and 1‘s, where 0 means empty and 1 means not empty, and an integer n, return if n new flowers can be planted in ...

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Question 323. First Unique Character in a String LeetCode Solution Problem Statement First Unique Character in a String LeetCode Solution – Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1. Example Test Case 1: Input: s = “leetcode” Output: 0 Test Case 2: Input: s = “aabb” Output: -1 Explanation ...

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Question 324. Analyze User Website Visit Pattern LeetCode Solution Problem Statement Analyze User Website Visit Pattern LeetCode Solution – You are given two string arrays username and website and an integer array timestamp. All the given arrays are of the same length and the tuple [username[i], website[i], timestamp[i]] indicates that the user username[i] visited the website website[i] at time timestamp[i]. A pattern is a list of three websites (not necessarily distinct). For example, ["home", ...

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Question 325. Invert Binary Tree LeetCode Solution Problem Statement: Invert Binary Tree LeetCode Solution – In this question, Given a root of any binary tree, the solution is required to invert the binary tree meaning the left tree should become the right tree and vice versa.   Explanation We can ask ourselves which tree traversal would be ...

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Question 326. Closest Binary Search Tree Value Leetcode Solution Problem Statement : Closest Binary Search Tree Value Leetcode Solution – Given the root of a binary search tree and a target value, return the value in the BST that is closest to the target. Example : Example 1 Input: root = [4,2,5,1,3], target = 3.714286 Output: 4 Example 2 Input: root = [1], target ...

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Question 327. Partition List Leetcode Solution Problem Statement : Partition List Leetcode Solution – Given the head of a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x. You should preserve the original relative order of the nodes in each of the two partitions. Example : Example 1  Input: head = ...

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Question 328. Design Browser History LeetCode Solution Problem Statement Design Browser History LeetCode Solution – You have a browser with one tab where you start on the homepage and you can visit another url, get back in the history number of steps or move forward in the history number of steps. Implement the BrowserHistory class: BrowserHistory(string homepage) Initializes the object with the homepage of the ...

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Question 329. Evaluate Reverse Polish Notation LeetCode Solution Problem Statement Evaluate Reverse Polish Notation LeetCode Solution – Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, and /. Each operand may be an integer or another expression. Note that the division between two integers should truncate toward zero. It is guaranteed that the given ...

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Question 330. 3Sum Closest LeetCode Solution Problem Statement 3Sum Closest LeetCode Solution – Given an integer array nums of length n and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would have exactly one solution. Input: nums = [-1,2,1,-4], target = 1 Output: ...

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Question 331. Largest Plus Sign Leetcode Solution Problem Statement : Largest Plus Sign Leetcode Solution – You are given an integer n. You have an n x n binary grid with all values initially 1‘s except for some indices given in the array mines. The ith element of the array mines is defined as mines[i] = [xi, yi] where grid[xi][yi] == 0. Return the order of the largest axis-aligned plus ...

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Question 332. Contiguous Array LeetCode Solution Problem Statement Contiguous Array LeetCode Solution – Given a binary array nums, return the maximum length of a contiguous subarray with an equal number of 0 and 1. Input: nums = [0,1] Output: 2 Explanation: [0, 1] is the longest contiguous subarray with an equal number of 0 and 1. Explanation Now what we ...

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Question 333. N-Queens LeetCode Solution Problem Statement N-Queens LeetCode Solution – The n-queens puzzle is the problem of placing n queens on a n x n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. You may return the answer in any order. Each solution contains a distinct board configuration of the ...

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Question 334. Largest Rectangle in Histogram LeetCode Solution Problem Statement Largest Rectangle in Histogram LeetCode Solution – Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram. Example Test Case 1: Input: heights = [2, 1, 5, 6, 2, 3] Output: 10 Explanation: ...

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Question 335. Regular Expression Matching Regular Expression Matching LeetCode Solution Problem Statement Regular Expression Matching Regular Expression Matching LeetCode Solution – Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where: '.' Matches any single character.​​​​ '*' Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). Example Test Case 1: Input: ...

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Question 336. Binary Tree Right Side View LeetCode Solution Problem Statement Binary Tree Right Side View LeetCode Solution – Given the root of a binary tree, imagine yourself standing on the right side of it, and return the values of the nodes you can see ordered from top to bottom. Example Test Case 1: Input: root = [1, 2, 3, null, 5, null, ...

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Question 337. Zigzag Conversion LeetCode Solution Problem Statement Zigzag Conversion LeetCode Solution – The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) P A H N A P L S I I G Y I ...

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Question 338. Maximize Distance to Closest Person LeetCode Solution Problem Statement Maximize Distance to Closest Person LeetCode Solution – You are given an array representing a row of seats where seats[i] = 1 represents a person sitting in the ith seat, and seats[i] = 0 represents that the ith seat is empty (0-indexed). There is at least one empty seat, and at least one person sitting. Alex wants to ...

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Question 339. Minesweeper LeetCode Solution Problem Statement Minesweeper LeetCode Solution – Let’s play the minesweeper game (Wikipedia, online game)! You are given an m x n char matrix board representing the game board where: 'M' represents an unrevealed mine, 'E' represents an unrevealed empty square, 'B' represents a revealed blank square that has no adjacent mines (i.e., above, below, left, right, and all ...

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Question 340. Time Based Key-Value Store LeetCode Solution Problem Statement Time Based Key-Value Store LeetCode Solution – Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key’s value at a certain timestamp. Implement the TimeMap class: TimeMap() Initializes the object of the data structure. void set(String key, String ...

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Question 341. Find Median from Data Stream LeetCode Solution Problem Statement Find Median from Data Stream LeetCode Solution – The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value and the median is the mean of the two middle values. For example, for arr = [2,3,4], the median ...

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Question 342. Permutation in String Leetcode Solution Problem Statement : Permutation in String Leetcode Solution – Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise. In other words, return true if one of s1‘s permutations is the substring of s2. Example : Example 1  Input: s1 = "ab", s2 = "eidbaooo" Output: true Explanation: s2 contains one permutation of s1 ("ba"). ...

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Question 343. Asteroid Collision LeetCode Solution Problem Statement Asteroid Collision LeetCode Solution – We are given an array asteroids of integers representing asteroids in a row. For each asteroid, the absolute value represents its size, and the sign represents its direction (positive meaning right, negative meaning left). Each asteroid moves at the same speed. Find out the state ...

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Question 344. Diagonal Traverse LeetCode Solution Problem Statement Diagonal Traverse LeetCode Solution – Given an m x n matrix mat, return an array of all the elements of the array in a diagonal order. Input: mat = [[1,2,3],[4,5,6],[7,8,9]] Output: [1,2,4,7,5,3,6,8,9] Explanation Consider the indices of the diagonals of an NxM matrix. Let’s use a 4×4 matrix as an example: ...

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Question 345. Longest Increasing Path in a Matrix LeetCode Solution Problem Statement Longest Increasing Path in a Matrix LeetCode Solution – Given an m x n integers matrix, return the length of the longest increasing path in matrix. From each cell, you can either move in four directions: left, right, up, or down. You may not move diagonally or move outside the boundary (i.e., wrap-around is not allowed). Input: ...

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Question 346. Number of Closed Islands Leetcode Solution Problem Statement : Number of Closed Islands Leetcode Solution – Given a 2D grid consisting of 0s (land) and 1s (water).  An island is a maximal 4-directionally connected group of 0s and a closed island is an island totally (all left, top, right, bottom) surrounded by 1s. Return the number of closed islands. Example : Example 1  Input: grid = [[1,1,1,1,1,1,1,0],[1,0,0,0,0,1,1,0],[1,0,1,0,1,1,1,0],[1,0,0,0,0,1,0,1],[1,1,1,1,1,1,1,0]] Output: 2 Explanation: Islands in gray ...

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Question 347. Serialize and Deserialize Binary Tree LeetCode Solution Problem Statement Serialize and Deserialize Binary Tree LeetCode Solution – Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in ...

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Question 348. Binary Tree Maximum Path Sum LeetCode Solution Problem Statement Binary Tree Maximum Path Sum LeetCode Solution – A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that the path does not need ...

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Question 349. Robot Bounded In Circle LeetCode Solution Problem Statement Robot Bounded In Circle LeetCode Solution – On an infinite plane, a robot initially stands at (0, 0) and faces north. Note that: The north direction is the positive direction of the y-axis. The south direction is the negative direction of the y-axis. The east direction is the positive direction of the x-axis. The west direction is the ...

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Question 350. Minimum Knight Moves LeetCode Solution Problem Statement Minimum Knight Moves LeetCode Solution – In an infinite chessboard with coordinates from -infinity to +infinity, you have a knight at square [0, 0]. A knight has 8 possible moves it can make, as illustrated below. Each move is two squares in a cardinal direction, then one square in an orthogonal direction. Return the minimum number ...

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Question 351. Binary Tree Zigzag Level Order Traversal LeetCode Solution Problem Statement Binary Tree Zigzag Level Order Traversal LeetCode Solution – Given the root of a binary tree, return the zigzag level order traversal of its nodes’ values. (i.e., from left to right, then right to left for the next level and alternate between). Input: root = [3,9,20,null,null,15,7] Output: [[3],[20,9],[15,7]] Explanation We ...

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Question 352. Find the Duplicate Number LeetCode Solution Problem Statement Find the Duplicate Number LeetCode Solution – Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number. You must solve the problem without modifying the array nums and uses only constant extra space. Input: nums = [1,3,4,2,2] Output: 2 Explanation ...

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Question 353. Snakes and Ladders LeetCode Solution Problem Statement Snakes and Ladders LeetCode Solution – You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. board[n - 1][0]) and alternating directions in each row. You start on the square 1 of the board. In each move, ...

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Question 354. Missing Element in Sorted Array LeetCode Solution Problem Statement: Missing Element in Sorted Array LeetCode Solution – Given an integer array nums which are sorted in ascending order and all of its elements are unique and given also an integer k, return the kth missing number starting from the leftmost number of the array. Example: Example 1 Input: nums = [4,7,9,10], k = ...

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Question 355. Path Sum II LeetCode Solution Problem Statement : Path Sum II LeetCode Solution – Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path should be returned as a list of the node values, not node references. A root-to-leaf path is a path starting from ...

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Question 356. Alien Dictionary LeetCode Solution Problem Statement Alien Dictionary LeetCode Solution – There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you. You are given a list of strings words from the alien language’s dictionary, where the strings in words are sorted lexicographically by the rules of this new language. ...

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Question 357. Product of Array Except Self LeetCode Solution Problem Statement Product of Array Except Self LeetCode Solution – Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division ...

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Question 358. Design Skiplist LeetCode Solution Problem Statement Design Skiplist LeetCode Solution – Design a Skiplist without using any built-in libraries. A skip list is a data structure that takes O(log(n)) time to add, erase and search. Compared with the tree and red-black tree which has the same function and performance, the code length of Skiplist can be comparatively ...

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Question 359. Longest Nice Substring LeetCode Solution Problem Statement : Longest Nice Substring LeetCode Solution – A string s is nice if, for every letter of the alphabet that s contains, it appears both in uppercase and lowercase. For example, “abABB” is nice because ‘A’ and ‘a’ appear, and ‘B’ and ‘b’ appear. However, “abA” is not because ‘b’ appears, but ‘B’ does not. Given a string s, return the longest substring of s that is nice. If there are multiple, return the substring of ...

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Question 360. Palindrome Permutation LeetCode Solution Problem Statement Palindrome Permutation LeetCode Solution – We are given a string and asked if a permutation of the given string could form a palindrome. Examples & Explanations Example 1: Input: s = "code" Output: false Explanation: we can not arrange letters of "code" to form a palindrome Example 2: ...

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Question 361. Intersection of Two Linked Lists LeetCode Solution Problem Statement Intersection of Two Linked Lists LeetCode Solution – We are given the heads of two strongly linked-lists headA and headB. It is also given that the two linked lists may intersect at some point. We are asked to return the node at which they intersect or null if ...

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Question 362. Permutation Sequence LeetCode Solution Problem Statement Permutation Sequence LeetCode Solution – The set [1, 2, 3, ..., n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, we get the following sequence for n = 3: "123" "132" "213" "231" "312" "321" Given n and k, return the kth permutation sequence. Example Test Case 1: Input: n ...

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Question 363. Search Suggestions System LeetCode Solution Problem Statement Search Suggestions System LeetCode Solution – You are given an array of strings products and a string searchWord. Design a system that suggests at most three product names from products after each character of searchWord is typed. Suggested products should have a common prefix with searchWord. If there are more than three products with a ...

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Question 364. Rotate Image LeetCode Solution Problem Statement Rotate Image LeetCode Solution – You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation. Example Test Case 1: Input: ...

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Question 365. Peeking Iterator LeetCode Solution Problem Statement Peeking Iterator LeetCode Solution – Design an iterator that supports the peek operation on an existing iterator in addition to the hasNext and the next operations. Implement the PeekingIterator class: PeekingIterator(Iterator<int> nums) Initializes the object with the given integer iterator iterator. int next() Returns the next element in the array and moves the pointer to the next element. boolean ...

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Question 366. Kth Smallest Element in a BST Leetcode Solution Problem Statement Kth Smallest Element in a BST Leetcode Solution – Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree. Examples: Input: root = [3,1,4,null,2], k = 1 Output: 1   Input: root = [5,3,6,2,4,null,null,1], k ...

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Question 367. Find Leaves of Binary Tree LeetCode Solution Problem Statement Find Leaves of Binary Tree LeetCode Solution – Given the root of a binary tree, collect a tree’s nodes as if you were doing this: Collect all the leaf nodes. Remove all the leaf nodes. Repeat until the tree is empty. Example Test Case 1: Input: root = [1, 2, 3, ...

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Question 368. Top K Frequent Words LeetCode Solution Problem Statement Top K Frequent Words LeetCode Solution – Given an array of strings words and an integer k, return the k most frequent strings. Return the answer sorted by the frequency from highest to lowest. Sort the words with the same frequency by their lexicographical order. Example Test Case 1: Input: words = [“i”,”love”,”leetcode”,”i”,”love”,”coding”] k = 2 Output: [“i”,”love”] Explanation ...

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Question 369. Parallel Courses II LeetCode Solution Problem Statement Parallel Courses II LeetCode Solution- You are given an integer n, which indicates that there are n courses labeled from 1 to n. You are also given an array relations where relations[i] = [prevCoursei, nextCoursei], representing a prerequisite relationship between course prevCoursei and course nextCoursei: course prevCoursei have to be taken before the course nextCoursei. Also, you are given the ...

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Question 370. Merge Sorted Array LeetCode Solution Problem Statement Merge Sorted Array LeetCode Solution – You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively. Merge nums1 and nums2 into a single array sorted in non-decreasing order. The final sorted array should not be returned by the function, but instead be stored inside the array nums1. ...

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Question 371. Employee Free Time LeetCode Solution Problem Statement Employee Free Time LeetCode Solution – We are given a list schedule of employees, which represents the working time for each employee. Each employee has a list of non-overlapping Intervals, and these intervals are in sorted order. Return the list of finite intervals representing the common, positive-length free time for all employees, also in ...

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Question 372. The Maze III LeetCode Solution Problem Statement The Maze III LeetCode Solution – There is a ball in a maze with empty spaces (represented as 0) and walls (represented as 1). The ball can go through the empty spaces by rolling up, down, left or right, but it won’t stop rolling until hitting a wall. When the ball stops, ...

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Question 373. Swapping Nodes in a Linked List Leetcode Solution Problem Statement Swapping Nodes in a Linked List Leetcode Solution – You are given the head of a linked list, and an integer k.Return the head of the linked list after swapping the values of the kth node from the beginning and the kth node from the end (the list is 1-indexed). Example: Input: head = [1,2,3,4,5], k = 2 ...

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Question 374. Find Minimum in Rotated Sorted Array II LeetCode Solution Problem Statement Find Minimum in Rotated Sorted Array II LeetCode Solution – Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,4,4,5,6,7] might become: [4,5,6,7,0,1,4] if it was rotated 4 times. [0,1,4,4,5,6,7] if it was rotated 7 times. Notice that rotating an array [a[0], a[1], a[2], ..., a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], ...

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Question 375. Delete Node in a Linked List Leetcode Solution Problem Statement : Delete Node in a Linked List Leetcode Solution – Write a function to delete a node in a singly-linked list. You will not be given access to the head of the list, instead, you will be given access to the node to be deleted directly. It is guaranteed that the node to be deleted is not ...

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Question 376. Number of Distinct Islands Leetcode Solution Problem Statement The Number of Distinct Islands LeetCode Solution – “Number of Distinct Islands” states that given a n x m binary matrix. An island is a group of 1‘s (representing land) connected 4-directionally (horizontal or vertical). An island is considered to be the same as another if and only if one island ...

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Question 377. Find if Path Exists in Graph Leetcode Solution Problem Statement Find if Path Exists in Graph Leetcode Solution – There is a bi-directional graph with n vertices, where each vertex is labeled from 0 to n - 1 (inclusive). The edges in the graph are represented as a 2D integer array edges, where each edges[i] = [ui, vi] denotes a bi-directional edge between vertex ui and vertex vi. Every vertex pair ...

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Question 378. Ugly Number II LeetCode Solution Problem Statement Ugly Number II LeetCode Solution – An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5. Given an integer n, return the nth ugly number. Input: n = 10 Output: 12 Explanation: [1, 2, 3, 4, 5, 6, 8, 9, 10, 12] is the sequence of the first 10 ...

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Question 379. Find a Peak Element II LeetCode Solution Problem Statement Find a Peak Element II LeetCode Solution – A peak element in a 2D grid is an element that is strictly greater than all of its adjacent neighbors to the left, right, top, and bottom. Given a 0-indexed m x n matrix mat where no two adjacent cells are equal, find any peak element mat[i][j] and return the length 2 array [i,j]. You may assume ...

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Question 380. Combination Sum IV LeetCode Solution Problem Statement Combination Sum IV LeetCode Solution – Given an array of distinct integers nums and a target integer target, return the number of possible combinations that add up to target. The test cases are generated so that the answer can fit in a 32-bit integer. Input: nums = [1,2,3], target = 4 Output: 7 Explanation: The possible ...

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Question 381. String to Integer (atoi) LeetCode Solution Problem Statement The String to Integer (atoi) Leetcode Solution -“String to Integer (atoi)” states that Implementing the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++’s atoi function). The algorithm for myAtoi(string s) is as follows: Read in and ignore any leading whitespace. Check if the next character (if ...

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Question 382. Restore IP Addresses Leetcode Solution Problem Statement The Restore IP Addresses LeetCode Solution – “Restore IP Addresses” states that given the string which contains only digits, we need to return all possible valid IP Addresses in any order that can be formed by inserting dots into the string. Note that we’re not allowed to return ...

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Question 383. String Compression LeetCode Solution Problem Statement String Compression LeetCode Solution – Given an array of characters chars, compress it using the following algorithm: Begin with an empty string s. For each group of consecutive repeating characters in chars: If the group’s length is 1, append the character to s. Otherwise, append the character followed by the group’s length. The compressed string ...

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Question 384. Check Completeness of a Binary Tree LeetCode Solution Problem Statement Check Completeness of a Binary Tree LeetCode Solution – Given the root of a binary tree, determine if it is a complete binary tree. In a complete binary tree, every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. ...

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Question 385. Graph Valid Tree LeetCode Solution Problem Statement Graph Valid Tree LeetCode Solution – Given the edges of a graph, check if the edges make up a valid tree. If yes, return true and false otherwise. The edges are given as a 2D array of size n*2 Examples & Explanations Example 1: Input: n = 5, ...

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Question 386. Spiral Matrix II Leetcode Solution Problem Statement This question Spiral Matrix II is very similar to  Spiral Matrix  Please try to attempt the above question to get a better idea before solving this problem. In this question, we are asked to generate a matrix of size n*n having elements in spiral order, and only n ...

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Question 387. Web Crawler LeetCode Solution Problem Statement Web Crawler LeetCode Solution – Given a URL startUrl and an interface HtmlParser, implement a web crawler to crawl all links that are under the same hostname as startUrl. Return all URLs obtained by your web crawler in any order. Your crawler should: Start from the page: startUrl Call HtmlParser.getUrls(url) to get all URLs from a webpage of ...

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Question 388. One Edit Distance LeetCode Solution Problem Statement One Edit Distance LeetCode Solution – Given two strings s and t, return true if they are both one edit distance apart, otherwise return false. A string s is said to be one distance apart from a string t if you can: Insert exactly one character into s to get t. Delete exactly one character from s to get t. Replace exactly one character of s with a different character to get t. Input: ...

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Question 389. Possible Bipartition LeetCode Solution Problem Statement Possible Bipartition LeetCode Solution – We want to split a group of n people (labeled from 1 to n) into two groups of any size. Each person may dislike some other people, and they should not go into the same group. Given the integer n and the array dislikes where dislikes[i] = [ai, bi] indicates that the person labeled ai does ...

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Question 390. Employee Importance LeetCode Solution Problem Statement Employee Importance LeetCode Solution – You have a data structure of employee information, including the employee’s unique ID, importance value, and direct subordinates’ IDs. You are given an array of employees employees where: employees[i].id is the ID of the ith employee. employees[i].importance is the important value of the ith employee. employees[i].subordinates is a list of the ...

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Question 391. Sign of the Product of an Array LeetCode Solution Problem Statement Sign of the Product of an Array LeetCode Solution – There is a function signFunc(x) that returns: 1 if x is positive. -1 if x is negative. 0 if x is equal to 0. You are given an integer array nums. Let product be the product of all values in the array nums. Return signFunc(product). Input: nums = [-1,-2,-3,-4,3,2,1] Output: 1 Explanation: The product ...

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Question 392. Kill Process LeetCode Solution Problem Statement Kill Process LeetCode Solution – You have n processes forming a rooted tree structure. You are given two integer arrays pid and ppid, where pid[i] is the ID of the ith process and ppid[i] is the ID of the ith process’s parent process. Each process has only one parent process but may have multiple children processes. Only one process has ppid[i] = 0, ...

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Question 393. Maximum Product of Splitted Binary Tree LeetCode Solution Problem Statement Maximum Product of Splitted Binary Tree LeetCode Solution – Given the root of a binary tree, split the binary tree into two subtrees by removing one edge such that the product of the sums of the subtrees is maximized. Return the maximum product of the sums of the two subtrees. ...

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Question 394. Subsequence of Size K With the Largest Even Sum LeetCode Solution Problem Statement The Subsequence of Size K With the Largest Even Sum LeetCode Solution – “Subsequence of Size K With the Largest Even Sum” states given an array nums and an integer k, the task here is to find the largest even sum of any subsequence from array nums which is ...

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Question 395. Symmetric Tree LeetCode Solution Leetcode Solution Problem Statement The Symmetric Tree LeetCode Solution – “Symmetric Tree” states that given the root of the binary tree and we need to check if the given binary tree is a mirror of itself(symmetric around its center) or not? If Yes, we need to return true otherwise, false. Example:   ...

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Question 396. Design Hit Counter LeetCode Solution Problem Statement Design Hit Counter LeetCode Solution – Design a hit counter which counts the number of hits received in the past 5 minutes (i.e., the past 300 seconds). Your system should accept a timestamp parameter (in seconds granularity), and you may assume that calls are being made to the system in chronological order (i.e., timestamp is monotonically increasing). ...

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Question 397. Minimum Moves to Equal Array Elements LeetCode Solution Problem Statement Minimum Moves to Equal Array Elements LeetCode Solution – Given an integer array nums of size n, return the minimum number of moves required to make all array elements equal. In one move, you can increment n - 1 elements of the array by 1. Example 1: Input  1: nums = [1, 2, 3] Output: ...

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Question 398. Jump Game Leetcode Solution Problem Statement Jump Game Leetcode Solution – You are given an integer array nums. You are initially positioned at the array’s first index, and each element in the array represents your maximum jump length at that position. Return true if you can reach the last index, or false otherwise. Example: Input 1: nums = [2, ...

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Question 399. Linked List Cycle II LeetCode Solution Problem Statement Linked List Cycle II LeetCode Solution – Given the head of a linked list, return the node where the cycle begins. If there is no cycle, return null. There is a cycle in a linked list if there is some node in the list that can be reached again by continuously ...

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Question 400. Consecutive Characters LeetCode Solution Problem Statement Consecutive Characters LeetCode Solution – The power of the string is the maximum length of a non-empty substring that contains only one unique character. Given a string s, return the power of s. Input: s = "leetcode" Output: 2 Explanation: The substring "ee" is of length 2 with the character 'e' only. Explanation ...

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Question 401. Word Pattern LeetCode Solution Problem Statement Word Pattern LeetCode Solution – We are given 2 strings – “s” and “pattern”, we need to find if the pattern follows s. Follows here means full match. More formally, we can for every pattern[i] there should only be one s[i] and vice versa i.e. there is a ...

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Question 402. Maximum Product of Three Numbers LeetCode Solution Problem Statement Maximum Product of Three Numbers LeetCode Solution – We are given an array, the question asks us to calculate the maximum product of any 3 numbers. Examples Example 1: Input: nums = [1,2,3] Output: 6 Example 2: Input: nums = [1,2,3,4] Output: 24 Example 3: Input: nums = ...

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Question 403. Excel Sheet Column Title LeetCode Solution Problem Statement Excel Sheet Column Title LeetCode Solution – We are given a column number (let’s call it colNum) and need to return its corresponding column title as it appears in an excel sheet For example A -> 1 B -> 2 C -> 3 … Z -> 26 AA ...

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Question 404. Valid Perfect Square LeetCode Solution Problem Statement Valid Perfect Square LeetCode Solution – Given a positive integer num, write a function that returns True if num is a perfect square else False. Follow up: Do not use any built-in library function such as sqrt. Input: num = 16 Output: true Explanation A boundary for our solution is fixed. for any number ...

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Question 405. Random Pick Index LeetCode Solution Problem Statement Random Pick Index LeetCode Solution- We are given a constructor of class “Solution” and a function “pick” of type int. We are required to implement the “Solution” class as Solution(int[] nums) Initializes the object with the array nums. int pick(int target) Picks a random index i from nums where nums[i] == target. If there are multiple ...

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Question 406. Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution Problem Statement The Find Two Non-overlapping Sub-arrays Each With Target Sum LeetCode Solution – “Find Two Non-overlapping Sub-arrays Each With Target Sum” states that you are given an integer array nums and an integer target, the task here is to find two non-overlapping subarrays from array nums such that the ...

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Question 407. Strobogrammatic Number LeetCode Solution Problem Statement Strobogrammatic Number LeetCode Solution – Given a string num which represents an integer, return true if num is a strobogrammatic number. A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Example Test Case 1: Input: num =  “69” Output: true Test Case 2: Input: num =  “692” Output: false Explanation ...

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Question 408. Merge Two Binary Trees LeetCode Solution Problem Statement Merge Two Binary Trees LeetCode Solution – You are given two binary trees root1 and root2. Imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not. You need to merge the two trees into ...

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Question 409. Subarray Product Less Than K LeetCode Solution Problem Statement Subarray Product Less Than K LeetCode Solution – Given an array of integers nums and an integer k, return the number of contiguous subarrays where the product of all the elements in the subarray is strictly less than k. Example Test Case 1: Input: inputArr = [10, 5, 2, 6] k = 100 ...

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Question 410. Reverse Only Letters LeetCode Solution Problem Statement Reverse Only Letters LeetCode Solution – Given a string s, reverse the string according to the following rules: All the characters that are not English letters remain in the same position. All the English letters (lowercase or uppercase) should be reversed. Return s after reversing it. Input: s = "ab-cd" ...

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Question 411. Number of Days Between Two Dates LeetCode Solution Problem Statement The question Number of Days Between Two Dates LeetCode Solution asks us to calculate the exact number of days between 2 given dates including leap years. The dates are given as strings in the format YYYY-MM-DD. It is also given that the input dates are valid dates between ...

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Question 412. Encoded String With Shortest Length LeetCode Solution Problem Statement Encoded String With Shortest Length LeetCode Solution – Given a string s, encode the string such that its encoded length is the shortest. The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. k should be a positive integer. If an encoding process does not make the ...

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Question 413. Next Greater Element III LeetCode Solution Problem Statement The problem, Next Greater Element III LeetCode Solution states that you are given a positive integer n and you need to find the next greatest integer using the digits present in n only. If there does not exist any such integer, you need to print -1. Moreover, the new ...

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Question 414. Edit Distance LeetCode Solution Problem Statement The problem Edit Distance LeetCode Solution states that you are given two strings word1 and word2 and you need to convert word1 into word2 in minimum operations. The operations that can be performed on the string are – Insert a character Delete a character Replace a character Examples Test Case ...

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Question 415. Find All Duplicates in an Array LeetCode Solution Problem Statement The problem, Find All Duplicates in an Array LeetCode Solution states that you are given an array of size n containing elements in the range [1,n]. Each integer can appear either once or twice and you need to find all the elements that appear twice in the array. Examples ...

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Question 416. Move Zeroes LeetCode Solution Problem Statement The problem, Move Zeroes LeetCode Solution states that you are given an array containing zero and non-zero elements and you need to move all the zeroes to the end of the array, maintaining the relative order of non-zero elements in the array. You also need to implement an in-place ...

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Question 417. Single Number Leetcode Solution Problem Statement Single Number Leetcode Solution – We are given a non-empty array of integers and need to find an element that appears exactly once. It is given in the question that every element appears twice except for one. Example 1: Input: nums = [2,2,1] Output: 1 Example 2: Input: ...

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Question 418. Number of Provinces Leetcode Solution Problem Statement Number of Provinces Leetcode Solution – We are given an adjacency matrix representation of a graph and need to find the number of provinces. Here province is a group of directly or indirectly connected cities and no other cities outside of the group. Example Example 1: Input: isConnected ...

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Question 419. 01 Matrix LeetCode Solution Problem Statement In this problem 01 Matrix LeetCode Solution, we need to find the distance of the nearest 0 for each cell of the given matrix. The matrix consists only of 0’s and 1’s and the distance of any two adjacent cells is 1. Examples Example 1: Input: mat = ...

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Question 420. Sort Characters By Frequency LeetCode Solution Problem Statement Sort Characters By Frequency LeetCode Solution – Given a string S, sort it in decreasing order based on the frequency of the characters. The frequency of a character is the number of times it appears in the string. Return the sorted string. If there are multiple answers, return any of them. Example for Sort Characters By ...

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Question 421. Maximum Value at a Given Index in a Bounded Array LeetCode Solution Problem Statement The problem Maximum Value at a Given Index in a Bounded Array LeetCode Solution says You are given three positive integers: n, index, and maxSum. You want to construct an array nums(0-indexed) that satisfies the following conditions: nums.length == n nums[i] is a positive integer where 0 <= i < n. ...

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Question 422. Non-decreasing Array LeetCode Solution Problem Statement Non-decreasing Array LeetCode Solution – given array nums with n integers, your task is to check if it could become non-decreasing by modifying at most one element. We define an array is non-decreasing if nums[index ] <= nums[index +1] holds for every index (0-based) such that (0 <= index <= n-2). ...

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Question 423. Longest Substring with At Most K Distinct Characters LeetCode Solution Problem Statement Longest Substring with At Most K Distinct Characters LeetCode Solution – Given a string S and an integer K, return the length of the longest substring of S that contains at most K distinct characters. Example: Test Case 1: Input: S = “bacc” K = 2 Output: 3 Test Case 2: Input: S = “ab” ...

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Question 424. Factorial Trailing Zeroes LeetCode Solution Problem Statement Factorial Trailing Zeroes LeetCode Solution – Given an integer n, return the number of trailing zeroes in n!. Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1. Input: n = 3 Output: 0 Explanation: 3! = 6, no trailing ...

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Question 425. Convert Sorted Array to Binary Search Tree LeetCode Solutions Problem Statement Convert Sorted Array to Binary Search Tree LeetCode Solutions says given an integer array nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree. A height-balanced binary tree is a binary tree in which the depth of the two subtrees of every node never differs by more ...

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Question 426. Word Ladder LeetCode Solution Problem Statement The Word Ladder LeetCode Solution – “Word Ladder” states that you are given a string beginWord, string endWord, and a wordList. We need to find the shortest transformation sequence length (if no path exists, print 0) from beginWord to endWord following the given conditions: All the Intermediate Words should ...

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Question 427. Best Meeting Point LeetCode Solution Problem Statement The Best Meeting Point LeetCode Solution says Given a binary grid grid of size m x n where each 1 determines the home of one friend, we want to return the minimal total travel distance where the total travel distance is the sum of the distances between the houses of ...

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Question 428. Longest Substring with At Least K Repeating Characters LeetCode Solution Problem Statement The problem Longest Substring with At Least K Repeating Characters LeetCode Solution says given a string S and an integer k, return the length of the longest substring of S such that the frequency of each character in this substring is greater than or equal to k. Example for Longest Substring with At Least ...

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Question 429. Same Tree LeetCode Solution Problem Statement The problem Same Tree says Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally identical, and the nodes have the same value. Example: Test Case ...

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Question 430. Spiral Matrix LeetCode Solution Problem Statement Spiral Matrix Problem says In Spiral Matrix we want to print all the elements of a matrix in a spiral form in the clockwise direction.   Approach for Spiral Matrix: Idea The problem can be implemented by dividing the matrix into loops and printing all the elements in each ...

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Question 431. Remove Duplicates from Sorted Array Leetcode Solution Problem Statement The Remove Duplicates from Sorted Array Leetcode Solution – says that you’re given an integer array sorted in non-decreasing order. We need to remove all duplicate elements and modify the original array such that the relative order of distinct elements remains the same and, report the value of ...

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Question 432. Largest BST Subtree LeetCode Solution Problem Statement The Largest BST Subtree LeetCode Solution problem says given the root of a binary tree, find the largest subtree, which is also a Binary Search Tree (BST), where the largest means subtree having the largest number of nodes. Note: A subtree must include all of its descendants. In a Binary ...

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Question 433. Sort Array By Parity LeetCode Solution Problem Statement The Sort Array By Parity LeetCode Solution – “Sort Array By Parity” states that you are given an integer array nums, move all the even integers at the beginning of the array followed by all the odd integers. Note: Return any array that satisfies this condition. Example: Input: Output: ...

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Question 434. Remove Nth Node From End of List Leetcode Solution Problem Statement The Remove Nth Node From End of List Leetcode Solution – states that you are given the head of a linked list and you need to remove the nth node from the end of this list. After deleting this node, return the head of the modified list. Example: Input: ...

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Question 435. Bulb Switcher LeetCode Solution Problem Statement Bulb Switcher LeetCode Solution – There are n bulbs that are initially off. You first turn on all the bulbs, then you turn off every second bulb. In the third round, you toggle every third bulb (turning on if it’s off or turning off if it’s on). For the ith round, you ...

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Question 436. Meeting Rooms II LeetCode Solution Problem Statement The Meeting Rooms II LeetCode Solution – “Meeting Rooms II” states that you are given an array of meeting time intervals “intervals” where “intervals[i] = [ start[i], end[i] ]”, return the minimum number of conference rooms required. Example: intervals = [[0,30],[5,10],[15,20]] 2 Explanation: Meeting one can be done ...

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Question 437. Longest Palindromic Substring LeetCode Solution Problem Statement The Longest Palindromic Substring LeetCode Solution – “Longest Palindromic Substring” states that You are Given a string s, return the longest palindromic substring in s. Note: A palindrome is a word that reads the same backward as forwards, e.g. madam. Example:   s = "babad" "bab" Explanation: All ...

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Question 438. Best Time to Buy and Sell Stock LeetCode Solution Problem Statement The Best Time to Buy and Sell Stock LeetCode Solution – “Best Time to Buy and Sell Stock” states that You are given an array of prices where prices[i] is the price of a given stock on an ith day. You want to maximize your profit by choosing ...

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Question 439. Median of Two Sorted Arrays LeetCode Solution Problem statement Median of Two Sorted Arrays LeetCode solution – In the problem “Median of Two Sorted Arrays”, we are given two sorted arrays nums1 and nums2 of size m and n respectively, and we have to return the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). Example nums1 = [1,3], ...

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Question 440. Number of Islands LeetCode Solution Problem Statement The number of Islands LeetCode Solution – “Number of Islands” states that you are given an m x n 2D binary grid which represents a map of ‘1’s (land) and ‘0’s (water), you have to return the number of islands. An island is surrounded by water and is ...

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Question 441. LRU Cache LeetCode Solution Question Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. Implement the LRUCache class: LRUCache(int capacity) Initialize the LRU cache with positive size capacity. int get(int key) Return the value of the key if the key exists, otherwise return -1. void put(int key, int value) Update the value of the key if the key exists. Otherwise, add the key-value pair to ...

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Question 442. Kth Largest Element in a Stream Leetcode Solution Problem Statement In this problem, we have to design a class KthLargest() that initially has an integer k and an array of integers. We need to write a parameterized constructor for it when an integer k and array nums are passed as arguments. The class also has a function add(val) that adds ...

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Question 443. Remove Linked List Elements Leetcode Solution Problem Statement In this problem, we are given a linked list with its nodes having integer values. We need to delete some nodes from the list which have value equal to val. The problem does not require to be solved in-place but we will discuss one such approach. Example List = ...

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Question 444. Minimum Moves to Equal Array Elements Leetcode Solution Problem Statement In this problem, we are given an array of integers. Also, we are allowed to perform a certain set of operations on this array. In one operation, we can increment ” n – 1″ (all elements except any one) elements in the array by 1. We need to ...

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Question 445. Count Good Nodes in Binary Tree Leetcode Solution Problem Statement In this problem a binary tree is given with its root. A node X in the tree is named good if in the path from root to X there are no nodes with a value greater than X. We have to return the number of good nodes in ...

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Question 446. Excel Sheet Column Number Leetcode Solution Problem Statement In this problem we are given a column title as appear in an Excel sheet, we have to return the column number that corresponds to that column title in Excel as shown below. Example #1 "AB" 28 #2 "ZY" 701 Approach To find column number for a particular ...

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Question 447. Number of Steps to Reduce a Number to Zero Leetcode Solution The problem Number of Steps to Reduce a Number to Zero Leetcode Solution states that given an integer. Find the minimum number of steps to convert the given integer to 0. You can perform either of the two steps, either subtract 1 or divide the integer by 2. The problem ...

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Question 448. Combinations Leetcode Solution The problem Combinations Leetcode Solution provides us with two integers, n, and k. We are told to generate all the sequences that have k elements picked out of n elements from 1 to n. We return these sequences as an array. Let us go through a few examples to get ...

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Question 449. Jewels and Stones Leetcode Solution The problem Jewels and Stones Leetcode Solution states that you are given two strings. One of them represents jewels and one of them represents stones. The string that contains jewels represents the characters that are jewels. We need to find the number of characters in the stones string that are ...

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Question 450. Count Odd Numbers in an Interval Range Leetcode Solution Problem Statement In this problem, we are given two non-negative integers low and high. We have to find how many odd numbers are there in the given interval range [ low, high ]. Example low = 3, high = 7 3 Explanation: The odd numbers between 3 and 7 are ...

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Question 451. Majority Element Leetcode Solution Problem Statement We are given an array of integers. We need to return the integer which occurs more than ⌊N / 2⌋ time in the array where ⌊ ⌋ is the floor operator. This element is called the majority element. Note that the input array always contains a majority element. ...

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Question 452. Convert a Number to Hexadecimal Leetcode Solution The problem Convert a Number to Hexadecimal Leetcode Solution provides us with an integer. Then asks us to convert the given integer in decimal number system to hexadecimal number system. More formally, the question requires us to convert an integer given in base 10 to a base 16 representation. We ...

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Question 453. Palindrome Linked List Leetcode Solution In the problem “Palindrome Linked List”, we have to check whether a given singly integer linked list is a palindrome or not. Example List = {1 -> 2 -> 3 -> 2 -> 1} true Explanation #1: The list is palindrome as all elements from the start and back are ...

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Question 454. Maximum Depth of Binary Tree Leetcode Solution Problem Statement In the problem a binary tree is given and we have to find out the maximum depth of the given tree. A binary tree’s maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Example 3 / ...

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Question 455. Maximum Depth of N-ary Tree Leetcode Solution In this problem, we are given an N-ary tree, that is, a tree that allows nodes to have more than 2 children. We need to find the depth of a leaf farthest from the root of the tree. This is called maximum depth. Note that the depth of a path ...

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Question 456. Rotate List Leetcode Solution The problem Rotate List Leetcode Solution provides us a linked list and an integer. We are told to rotate the linked list to the right by k places. So if we rotate a linked list k places to the right, in each step we take the last element from the ...

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Question 457. Pow(x, n) Leetcode Solution The problem “Pow(x, n) Leetcode Solution” states that you are given two numbers, one of which is a floating-point number and another an integer. The integer denotes the exponent and the base is the floating-point number. We are told to find the value after evaluating the exponent over the base. ...

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Question 458. Insert into a Binary Search Tree Leetcode Solution In this problem, we are given the root node of a Binary Search Tree containing integer values and an integer value of a node that we have to add in the Binary Search Tree and return its structure. After inserting the element into the BST, we have to print its ...

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Question 459. Merge Two Sorted Lists Leetcode Solutions Linked lists are quite like arrays in their linear properties. We can merge two sorted arrays to form an overall sorted array. In this problem, we have to merge two sorted linked lists in place to return a new list which contains elements of both lists in a sorted fashion. Example ...

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Question 460. Permutations Leetcode Solution The problem Permutations Leetcode Solution provides a simple sequence of integers and asks us to return a complete vector or array of all the permutations of the given sequence. So, before going into solving the problem. We should be familiar with permutations. So, a permutation is nothing but an arrangement ...

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Question 461. Two Sum Leetcode Solution In this problem, we have to find a pair of two distinct indices in a sorted array that their values add up to a given target. We can assume that the array has only one pair of integers that add up to the target sum. Note that the array is ...

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Question 462. Count Primes Leetcode Solutions In this problem, we are given an integer, N. The goal is to count how numbers less than N, are primes. The integer is constrained to be non-negative. Example 7 3 10 4 Explanation Primes less than 10 are 2, 3, 5 and 7. So, the count is 4. Approach(Brute ...

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Question 463. House Robber II Leetcode Solution In the “House Robber II” problem, a robber wants to rob money from different houses. The amount of money in the houses is represented through an array. We need to find the maximum sum of money that can be made by adding the elements in a given array according to ...

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Question 464. Sqrt(x) Leetcode Solution As the title says, we need to find the square root of a number. Let say the number is x, then Sqrt(x) is a number such that Sqrt(x) * Sqrt(x) = x. If the square root of a number is some decimal value, then we have to return the floor value of ...

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Question 465. Convert Sorted Array to Binary Search Tree Leetcode Solution Consider we are given a sorted array of integers. The goal is to build a Binary Search Tree from this array such that the tree is height-balanced. Note that a tree is said to be height-balanced if the height difference of left and right subtrees of any node in the ...

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Question 466. Water Bottles Leetcode Solution Problem statement In the problem ” Water Bottles” we are given two values namely” numBottle” which will store the total number of full water bottles and “numExchange” which will store the total number of empty water bottles we can exchange at a time and get a full water bottle. After ...

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Question 467. Swap Nodes in Pairs Leetcode Solutions The goal of this problem is to swap nodes of a given linked list in pairs, that is, swapping every two adjacent nodes. If we are allowed to swap just the value of the list nodes, the problem would be trivial. So, we are not allowed to modify the node ...

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Question 468. House Robber Leetcode Solution Problem Statement In this problem there are houses in a street and House robber has to rob these houses. But the problem is that he can’t rob more than one house successively i.e which are adjacent to each other. Given a list of non-negative integers representing the amount of money ...

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Question 469. Valid Anagrams In the problem “Valid Anagrams” we have given two strings str1 and str2. Find out that both the strings are anagrams or not. If they are anagrams return true else return false. Example Input: str1 = “abcbac” str2 = “aabbcc” Output: true Explanation: Since str2 can be formed by rearranging ...

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Question 470. Union and Intersection of two Linked Lists Given two linked lists, create another two linked lists to get union and intersection of the elements of existing lists. Example Input: List1: 5 → 9 → 10 → 12 → 14 List2: 3 → 5 → 9 → 14 → 21 Output: Intersection_list: 14 → 9 → 5 Union_list:   ...

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Question 471. Round Robin Scheduling The Round Robin scheduling is very much similar to FCFS. The only difference between RR and FCFS scheduling is, RR is preemptive scheduling whereas FCFS is non-preemptive scheduling. Every process is allocated to CPU in the ready queue for a single time slice. Here, a ready queue is similar to ...

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Question 472. Count ways to reach the nth stair using step 1, 2 or 3 The problem “Count ways to reach the nth stair using step 1, 2, or 3” states that you are standing on the ground. Now you need to reach the end of the staircase. So how many ways are there to reach the end if you can jump only 1, 2, ...

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Question 473. Write a function to get the intersection point of two Linked Lists Problem Statement The problem “Write a function to get the intersection point of two Linked Lists” states that you are given two linked lists. But they are not independent linked lists. They are connected at some point. Now you need to find this point of intersection of these two lists. ...

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Question 474. Cutting a Rod Problem Statement The problem “Cutting a Rod” states that you are given a rod of some particular length and prices for all sizes of rods which are smaller than or equal to the input length. That is we know the price for rods of length from 1 to n, considering ...

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Question 475. Check if any two intervals overlap among a given set of intervals Problem Statement The problem “Check if any two intervals overlap among a given set of intervals” states that you are given some set of intervals. Each interval consists of two values, one is starting time and the other is ending time. The problem statement asks to check if any of ...

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Question 476. Palindrome Number Problem Statement the problem “Palindrome Number” states that you are given an integer number. Check if it is a palindrome or not. Solve this problem without converting the given number into a string. Example 12321 true Explanation 12321 is a palindrome number because when we reverse 12321 it gives 12321 ...

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Question 477. Page Replacement Algorithms in Operating Systems What is Page Replacement? The modern operating systems use paging for memory management and many times there is a need for page replacement. Page replacement is the process of replacing a page that is currently present in the memory with a page that is needed but is not present in ...

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Question 478. Cuckoo sequence program Problem Statment Cuckoo sequence program or Cuckoo Hashing is a method used to solve the problem when a collision occurs in a Hash Table. Collisions are likely of two hash values of a hash function in a table. A collision occurs when two hash values for the same key occurs ...

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Question 479. Boolean Parenthesization Problem Problem Statement “ Boolean Parenthesization Problem ” states that we are given a sequence of true and false, and some boolean operators( AND, OR, XOR) in between them. We need to find the number of ways to parenthesize the given sequence such that the entire sequence results in TRUE. In ...

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Question 480. Count pairs from two linked lists whose sum is equal to a given value Problem Statement Problem “Count pairs from two linked lists whose sum is equal to a given value” state that you are given two linked lists and an integer value sum. The problem statement asked to find out how many total pair has a sum equal to the given value. Example ...

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Question 481. Word Wrap Problem Problem Statement The word wrap problem states that given a sequence of words as input, we need to find the number of words that can be fitted in a single line at a time. So, for doing this we put breaks in the given sequence such that the printed document ...

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Question 482. Find Number of Employees Under every Employee HashMaps are one of the most useful data structures. Find the number of employees under every employee is a problem that reminds me of the famous movie’s inception. Akin to dream in a dream. Here, we have an employee working under an employee and so on. Problem Statement So, what ...

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Question 483. Longest Increasing Subsequence We are provided with an array of integers that is unsorted and we have to find the longest increasing subsequence. The subsequence need not be consecutive The subsequence shall be increasing Let’s understand that better by a few examples. Example Input [9, 2, 5, 3, 7, 10, 8] Output 4 ...

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Question 484. K-th Distinct Element in an Array You are given an integer array A, print k-th distinct element in an array. The given array may contain duplicates and the output should print k-th distinct element among all unique elements in an array. If k is more than a number of distinct elements, then report it. Example Input: ...

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Question 485. Swap Nodes In Pairs In swap nodes in pairs problem, we have given a linked list consisting of n nodes. Swap every node at even index with it’s a right adjacent node at odd index() considering index starting from 0. Example Input : 1->2->3->4->NULL Output : 2->1->4->3->NULL Input : 1->2->3->4->5->6->7->NULL Output : 2->1->4->3->6->5->7->NULL Iterative Method Algorithm Create a ...

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Question 486. Leetcode Permutations In this leetcode problem premutation we have given an array of distinct integers, print all of its possible permutations. Examples Input arr[] = {1, 2, 3} Output 1 2 3 1 3 2 2 1 3 2 3 1 3 1 2 3 2 1 Input arr[] = {1, 2, ...

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Question 487. Sudoku Solver In the sudoku solver problem we have given a partially filled (9 x 9) sudoku, write a program to complete the puzzle. Sudoku must satisfy the following properties, Every number(1-9) must appear exactly once in a row and once in a column. Every number(1-9) must appear exactly once in a ...

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Question 488. Merge K Sorted Linked Lists Merge K sorted linked lists problem is so famous as per the interview point of view. This question asks so many times in big companies like Google, Microsoft, Amazon, etc.  As the name suggests we’ve been provided with k sorted linked lists. We have to merge them together into a ...

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Question 489. Merge Two Sorted Linked Lists In merge two sorted linked lists we have given head pointer of two linked lists, merge them such that a single linked list is obtained which has nodes with values in sorted order. return the head pointer of the merged linked list. Note: merge the linked list in-place without using ...

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Question 490. Find Median from data Stream In Find Median from the data Stream problem, we have given that integers are being read from a data stream. Find the median of all the elements read so far starting from the first integer till the last integer. Example Input 1: stream[ ] = {3,10,5,20,7,6} Output : 3 6.5 ...

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Question 491. House Robber The House Robber Problem states that, in a neighborhood in a city, there is a single row of n houses. A thief is planning to carry a heist in this neighborhood. He knows how much gold is concealed in each of the houses. However, in order to avoid triggering an ...

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Question 492. Word Break Word Break is a problem that beautifully illustrates a whole new concept. We have all heard of compound words. Words made up of more than two words. Today we have a list of words and all we’ve got to do is check if all the words from the dictionary can ...

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Question 493. Merge Two Sorted Lists Leetcode What is merge two sorted lists problem on leetcode? This is so interesting question asked so many times in compnies like Amazon, Oracle, Microsoft, etc. In this problem(Merge Two Sorted Lists Leetcode), we have given two linked lists. Both linked lists are in increasing order. Merge both linked list in ...

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Question 494. Reverse Nodes in K-Group Problem In Reverse Nodes in K-Group problem we have given a linked list, Reverse the linked list in a group of k and return the modified list. If the nodes are not multiple of k then reverse the remaining nodes. The value of k is always smaller or equal to ...

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Question 495. LRU Cache Implementation Least Recently Used (LRU) Cache is a type of method which is used to maintain the data such that the time required to use the data is the minimum possible. LRU algorithm used when the cache is full. We remove the least recently used data from the cache memory of ...

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Question 496. Merge Sort What is merge sort? Merge Sort is a Recursive Procedure. It is also a divide and conquers algorithm. Now we need to know what divide and conquer algorithm is? It’s a type of procedure in which we divide the problem into subproblems and divide them until we find the shortest ...

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Question 497. Valid Sudoku Valid Sudoku is a problem in which we have given a 9*9  Sudoku board. We need to find the given Sudoku is valid or not on the basis of the following rules: Each row must contain the digits 1-9 without repetition. Each column must contain the digits 1-9 without repetition. Every of the 9 3x3 sub-boxes ...

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Question 498. Add two numbers Add two numbers is a problem in which we have given two non-empty linked list representing a non-negative integer. The digit are store in reverse order and every node must contain only a single digit. Add the two numbers and print the result by using a linked list. Input Format ...

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Question 499. Sieve of Eratosthenes Sieve of Eratosthenes is an algorithm in which we find out the prime numbers less than N. Here N is an integer value. This is an efficient method to find out the prime numbers to a limit. By using this we can find out the prime numbers till 10000000. Here ...

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Question 500. N queen problem N queen problem using the concept of Backtracking. Here we place queen such that no queen under attack condition. The attack condition of the queens is if two queens are on the same column, row, and diagonal then they are under attack. Let’s see this by the below figure. Here ...

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Question 501. Serialize and Deserialize Binary Tree We have given a binary tree containing N number of nodes where each node has some value. We need to serialize and deserialize the binary tree. Serialize The process of storing a tree in a file without disturbing its structure is called serialization. DeserializeSerialize and Deserialize Binary Tree The process ...

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Question 502. Reverse a linked list Problem Statement The problem “reverse a linked list” states that we are given the head of the linked list. We have to reverse the linked list by changing the links between them and return the head of the reversed linked list. Example 10->20->30->40->NULL NULL<-10<-20<-30<-40 Explanation We have reversed the linked ...

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Question 503. Find Pair with Given Difference Problem Statement In the given unsorted array, find the pair of elements in the given array with given difference n. Example Input arr[] = {120, 30, 70, 20, 5, 6}, difference(n) = 40 Output [30, 70] Explanation Here the difference of 30 and 70 is equal to the value of ...

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Question 504. Insert Node in the Sorted Linked List Problem Statement In the “Insert Node in the Sorted Linked List” problem we have given a linked list. Insert a new node in the sorted linked list in a sorted way. After inserting a node in the sorted linked list the final linked list should be the sorted linked list. ...

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Question 505. Detect a loop in the Linked List Problem Statement In the “Detect a loop in the Linked List” problem we have given a linked list. Find whether there is loop or not. If there is a loop in the linked list then some node in the linked list will be pointing to one of the previous nodes ...

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