Palindrome Linked List

Difficulty

Easy

Question

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

Link

Palindrome Linked List

Solution

Solution loads pointers to list nodes into double-ended queue. Then, it compares both top and bottom values at once to establish whether the input is in fact a palindrome.

• Time complexity: O(n)
• Space complexity: O(1)