234. Palindrome Linked List ¶
Problem
Given the head
of a singly linked list, return true
if it is a palindrome or false
otherwise.
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 <= Node.val <= 9
Follow up: Could you do it in O(n)
time and O(1)
space?