Problem Statement Next Greater Element II LeetCode Solution – Given a circular integer array nums (i.e., the next element of nums[nums.length – 1] is nums[0]), return the next greater number for every element in nums. The next greater number of a number x is the first greater number to its traversing order next in the array, which means you could search …
Problem Statement Group Shifted Strings Leetcode Solution – We can shift a string by shifting each of its letters to its successive letter. For example, “abc” can be shifted to be “bcd”. We can keep shifting the string to form a sequence. For example, we can keep shifting “abc” to form the sequence: “abc” -> “bcd” …
Problem Statement: Camelcase Matching Leetcode Solution says that – Given an array of string “queries” and string “pattern”, return boolean array result where result[i] is true where “queries[i]” matches with “pattern”, false otherwise. A query word “queries[i]” matches with “pattern” if you can insert some lowercase English letters in “pattern” so …
Problem Statement Isomorphic Strings LeetCode Solution – Given two strings s and t, determine if they are isomorphic. Two strings s and t are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the …
Problem Statement Peak Index in a Mountain Array LeetCode Solution – An array arr a mountain if the following properties hold: arr.length >= 3 There exists some i with 0 < i < arr.length – 1 such that: arr[0] < arr[1] < … < arr[i – 1] < arr[i] arr[i] > arr[i + 1] > … > …
Problem Statement Valid Triangle Number LeetCode Solution – Given an integer array nums, return the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle. Input: nums = [2,2,3,4] Output: 3 Explanation: Valid combinations are: 2,3,4 (using the first 2) …
Problem Statement: Swim in Rising Water LeetCode Solution : You are given an n x n integer matrix grid where each value grid[i][j] represents the elevation at that point (i, j). The rain starts to fall. At time t, the depth of the water everywhere is t. You can swim from a square to another 4-directionally adjacent square if …
Problem Statement: The Monotonic Array Leetcode Solution – Given an array is monotonic if it is either monotone increasing or monotone decreasing. An array nums is monotone increasing if for all i <= j, nums[i] <= nums[j]. An array nums is monotone decreasing if for all i <= j, nums[i] >= nums[j]. Given an integer array nums, return true if the given …
Unique Binary Search Trees LeetCode Solution says that – Given an integer n, return the number of structurally unique BST’s (binary search trees) which has exactly n nodes of unique values from 1 to n. Example 1: Input: n = 3 Output: 5 Example 2: Input: n = 1 Output: 1 Constraints: 1 <= n <= 19 …
Problem Statement: Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution: RandomizedCollection is a data structure that contains a collection of numbers, possibly duplicates (i.e., a multiset). It should support inserting and removing specific elements and also removing a random element. Implement the RandomizedCollection class: RandomizedCollection() Initializes the empty RandomizedCollection object. bool insert(int val) Inserts an item val into …