LeetCode JavaScript 206: Reverse Linked List

Today, we will be discussing the popular LeetCode problem 206: Reverse Linked List. This problem deals with reversing a singly linked list using JavaScript. Linked lists are a fundamental data structure in computer science, and understanding how to manipulate them is crucial for any developer.

Problem Description

The problem statement for LeetCode 206 is as follows:

Reverse a singly linked list.

This means that given a linked list, we need to reverse the order of its elements. For example, if we have a linked list with elements 1 -> 2 -> 3 -> 4 -> 5, the reversed list would be 5 -> 4 -> 3 -> 2 -> 1.

Solution Approach

There are multiple approaches to solve this problem, but a common and efficient method is to use iterative or recursive algorithms. In JavaScript, we can accomplish this by manipulating the pointers of the linked list nodes.

Iterative Approach

The iterative approach involves iterating through the original linked list and changing the pointers to reverse the order of the elements. Here is a basic implementation of the iterative approach in JavaScript:

function reverseList(head) {
  let prev = null;
  let current = head;

  while (current) {
    let nextTemp = current.next;
    current.next = prev;
    prev = current;
    current = nextTemp;
  }

  return prev;
}

Recursive Approach

The recursive approach involves reversing the linked list in a recursive manner. Here is a basic implementation of the recursive approach in JavaScript:

function reverseList(head) {
  if (!head || !head.next) {
    return head;
  }

  let reversedList = reverseList(head.next);
  head.next.next = head;
  head.next = null;

  return reversedList;
}

Conclusion

Understanding and implementing solutions for problems like LeetCode 206 is essential for mastering JavaScript and data structures. By practicing such problems, you can enhance your problem-solving skills and become a more proficient developer.

For more tutorials and practice problems, check out LeetCode’s extensive collection of programming exercises. Happy coding!