Reverse Linked List (LeetCode #206)

Challenge Statement

• Given the head of a singly linked list, reverse the list, and return the reversed list.
• This challenge corresponds to LeetCode #206.

Constraints

• The number of nodes in the list is the range [0, 5000].
• -5000 <= Node.val <= 5000

Example 1:

Input: head = [1, 2, 3, 4, 5]
Output: [5, 4, 3, 2, 1]

Example 2:

Input: head = [1, 2]
Output: [2, 1]

Example 3:

Input: head = []
Output: []

Solution

Below is my solution and some test cases. This solution has a linear time complexity O(n) and a linear space complexity O(n), where n is the length of the input list.