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Palindrome Linked List

Explore how to verify whether a linked list is a palindrome by using fast and slow pointer strategies. Understand the problem constraints and implement solutions that maintain the linked list's original structure. This lesson helps you apply hands-on coding skills to solve palindrome detection efficiently.

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Statement

Given the head of a linked list, your task is to check whether the linked list is a palindrome or not. Return TRUE if the linked list is a palindrome; otherwise, return FALSE.

Note: The original structure of the linked list must remain unchanged before and after the checking process.

Constraints:

Let n be the number of nodes in a linked list.

  • 1≤1\leq n ≤500\leq500

  • 0≤0 \leq Node.value ≤9\leq 9.

Examples

Understand the problem

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

Palindrome Linked List

1.

What is the output if the following linked list is provided as input?

7 → 3 → 3 → 3 → 7

A.

TRUE

B.

FALSE

1 / 4

Figure it out!

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Sequence - Vertical
Drag and drop the cards to rearrange them in the correct sequence.
1
2
3
4
5
6

Try it yourself

Implement your solution in the following coding playground. We have also provided a useful code template that you may build on to solve this problem.

Java
usercode > Solution.java
// Definition for a Linked List node
// class ListNode {
//     int val;
//     ListNode next;
//     // Constructor
//     public ListNode(int val) {
//         this.val = val;
//         this.next = null;
//     }
// }
import ds_v1.LinkedList.ListNode;
import java.util.*;
public class Solution{
    public static boolean palindrome(ListNode head) {
      // Replace this placeholder return statement with your code
        return false;
    }
}
Palindrome Linked List