Reverse Linked List
Easy
Linked List
Recursion
Given the `head` of a singly linked list, reverse the list, and return *the reversed list*.
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: []

Constraints

  • •The number of nodes in the list is the range [0, 5000].
  • •-5000 <= Node.val <= 5000
Time Complexity
O(n)
Space Complexity
O(1)
14
Case 1
Input: [1,2,3,4,5]
Expected: [5,4,3,2,1]
Case 2
Input: [1,2]
Expected: [2,1]
Case 3
Input: []
Expected: []