Problem Statement: Invert Binary Tree LeetCode Solution : Given the root of a binary tree, invert the tree, and return its root. An inverted form of a Binary Tree is another Binary Tree with left and right children of all non-leaf nodes interchanged. You may also call it the mirror of the input tree. …
Problem Statement: Implement strStr() LeetCode Solution – Implement strStr(). Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Clarification: What should we return when needle is an empty string? This is a great question to ask during an interview. For the purpose of this problem, we …
Problem Statement: Contains Duplicate LeetCode Solution says that- Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Example 1: Input: nums = [1,2,3,1] Output: true Example 2: Input: nums = [1,2,3,4] Output: false Example 3: Input: nums = [1,1,1,3,3,4,3,2,4,2] Output: …
Problem Statement: Reverse Nodes in k-Group LeetCode Solution – Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. k is a positive integer and is less than or equal to the length of the linked list. If the number of nodes is …
Problem Statement: Single Element in a Sorted Array LeetCode Solution says that – You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once. Return the single element that appears only once. Your solution must run in O(log n) time …
Problem Statement: Find First and Last Position of Element in Sorted Array LeetCode Solution says that – given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not found in the array, return [-1, -1]. You must write an algorithm with O(log n) runtime complexity. …
Problem Statement: Fibonacci Number LeetCode Solution says 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 – 2), …
Problem Statement Find Peak Element LeetCode Solution says that – A peak element is an element that is strictly greater than its neighbors. Given a 0-indexed integer array nums, find a peak element, and return its index. If the array contains multiple peaks, return the index to any of the peaks. You may imagine …
Problem Statement Binary Search LeetCode Solution says that – Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [-1,0,3,5,9,12], target …
Problem Statement Container With Most Water LeetCode Solution says that – You are given an integer array height of length n. There are n vertical lines are drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container …