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Reverse Linked List

Explore how to reverse a singly linked list by applying in-place manipulation methods. This lesson guides you through understanding the problem, implementing the reversal, and optimizing node operations to efficiently update the list's head.

We'll cover the following...

Statement

Given the head of a singly linked list, reverse the linked list and return its updated head.

Constraints:

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

  • 1≤1 \leq n ≤500\leq 500
  • −5000≤-5000 \leq Node.value ≤5000\leq 5000

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:

Technical Quiz
1.

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

4 → 2 → 7 → 8 → 9 → 0 → 2

A.

9 → 0 → 2 → 8 → 4 → 2 → 7

B.

7 → 2 → 4 → 8 → 2 → 0 → 9

C.

2 → 0 → 9 → 8 → 7 → 2 → 4

D.

0 → 2 → 2 → 4 → 8 → 9

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

Try it yourself

Implement your solution in the following coding playground.

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 ListNode reverse(ListNode head) {



        // Replace this placeholder return statement with your code

        

        return head;

    }

}
Reverse Linked List