Grokking the Coding Interview: Patterns for Coding Questions

Solution: Problem Challenge 1: Palindrome LinkedList

## Problem Statement

Given the head of a **Singly LinkedList**, write a method to check if the **LinkedList is a palindrome or not**.

Your algorithm should use **constant space** and the input LinkedList should be in the original form once the algorithm is finished. The algorithm should have O(N) time complexity where ‘N’ is the number of nodes in the LinkedList.



**Example 1**:

```
Input: 2 -> 4 -> 6 -> 4 -> 2 -> null
Output: true
```

**Example 2**:

```
Input: 2 -> 4 -> 6 -> 4 -> 2 -> 2 -> null
Output: false
```

**Constraints:**

- The number of nodes in the list is in the range