https://leetcode.com/problems/palindrome-linked-list/ Given the head of a singly linked list, return true if it is a palindrome or false otherwise. * A palindrome is a sequence that reads the same forward and backward. Example 1: Input: head = [1,2,2,1] Output: true Example 2: Input: head = [1,2] Output: false Constraints: The number of nodes in the list is in the range [1, 10⁵] 0