LeetCode: Reverse Linked List

Reverse a singly linked list.

Posted on 6 Dec 2025 LeetCode Python

See original problem on leetcode.com

Difficulty: Medium

Solution

Three-pointer technique with previous, current, and next.

While current is not None:

Store current.next in next.
Set current.next to previous.
Move previous to current.
Move current to next.

Runtime

0 ms | Beats 100.00%

class Solution:
    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
        previous, current = None, head

        while current:
            next = current.next
            current.next = previous
            previous, current = current, next

        return previous