234\. Palindrome Linked List

Easy

Given the `head` of a singly linked list, return `true` if it is a palindrome.

**Example 1:**

![](https://assets.leetcode.com/uploads/2021/03/03/pal1linked-list.jpg)

**Input:** head = [1,2,2,1]

**Output:** true 

**Example 2:**

![](https://assets.leetcode.com/uploads/2021/03/03/pal2linked-list.jpg)

**Input:** head = [1,2]

**Output:** false 

**Constraints:**

*   The number of nodes in the list is in the range <code>[1, 10<sup>5</sup>]</code>.
*   `0 <= Node.val <= 9`

**Follow up:** Could you do it in `O(n)` time and `O(1)` space?