Leetcode

Problem Statement Description 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 operation. Examples Example 1: Input: nums = [1,2,3,4] Output: [24,12,8,6] Example 2: Input: nums = [-1,1,0,-3,3] Output: [0,0,9,0,0] Constraints 2 <= nums....

Problem Statement Description Given an integer array nums, find the subarray with the largest sum, and return its sum. Examples Example 1: Input: nums = [-2,1,-3,4,-1,2,1,-5,4] Output: 6 Explanation: The subarray [4,-1,2,1] has the largest sum 6. Example 2: Input: nums = [1] Output: 1 Explanation: The subarray [1] has the largest sum 1. Example 3: Input: nums = [5,4,-1,7,8] Output: 23 Explanation: The subarray [5,4,-1,7,8] has the largest sum 23....

Problem Statement Description 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. Examples 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: true Constraints 1 <= nums.length <= 105 -109 <= nums[i] <= 109 Key Insights This is a very simple problem that introduces the concept of a hash set....

Problem Statement Description Given the head of a singly linked list, return the middle node of the linked list. If there are two middle nodes, return the second middle node. Examples Example 1: flowchart LR a((1))-->b((2))-->c(3)-->d((4))-->e((5)) Input: head = [1,2,3,4,5] Output: [3,4,5] Explanation: The middle node of the list is node 3. Example 2: flowchart LR a((1))-->b((2))-->c((3))-->d(4)-->e((5))-->f((6)) Input: head = [1,2,3,4,5,6] Output: [4,5,6] Explanation: Since the list has two middle nodes with values 3 and 4, we return the second one....

Problem Statement Description Given the root of a binary tree, return the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root. The length of a path between two nodes is represented by the number of edges between them. Examples Example 1: flowchart TD a((1))-->b((2)) b-->c((4)) b-->d((5)) a-->e((3)) Input: root = [1,2,3,4,5] Output: 3 Explanation: 3 is the length of the path [4,2,1,3] or [5,2,1,3]....