Search⌘ K
AI Features
Home
Courses
Grokking the Coding Interview Patterns

Reverse Linked List

Explore how to efficiently reverse a singly linked list by manipulating its nodes in place. This lesson helps you understand constraints and apply step-by-step techniques to solve the problem, building proficiency in linked list algorithms commonly tested in coding interviews.

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