Question: 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 following the next poi...
Question: 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. Example 1: Input: head = [1,2,3,4,5] Output: [3,4,5] Explanation: The middle node of the list i...
Given the head of a singly linked list, reverse the list, and return the reversed list. Example 1: Question: Example 1: Input: head = [1,2,3,4,5] Output: [5,4,3,2,1] Example 2: Input: head = [1,2] Output: [2,1] Example 3: Input: head = [] Output: [] ...
Question: You are given the heads of two sorted linked lists list1 and list2. Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists. Return the head of the merged linked list. Example ...
Question: Given two strings s and t, return true if s is a subsequence of t, or false otherwise. A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the...
Question: 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 ord...