Practice/Apple/Leetcode 92. Reverse Linked List II

Leetcode 92. Reverse Linked List II

CodingOptional

Problem

Given the head of a singly linked list and two integers left and right where left <= right, reverse the nodes of the list from position left to position right (inclusive), and return the modified list.

The positions are 1-indexed, meaning the first node is at position 1.

Requirements

1. Reverse only the portion of the linked list between positions left and right
2. The rest of the list should remain unchanged
3. Modify the list in-place using O(1) extra space
4. Return the head of the modified linked list

Constraints

• The number of nodes in the list is in the range [1, 500]
• -500 <= Node.val <= 500
• 1 <= left <= right <= n where n is the length of the list

Examples

Example 1:

Input: head = 1 -> 2 -> 3 -> 4 -> 5, left = 2, right = 4 Output: 1 -> 4 -> 3 -> 2 -> 5 Explanation: We reverse the sublist from position 2 to 4, which contains nodes with values 2, 3, and 4

Example 2:

Input: head = 5, left = 1, right = 1 Output: 5 Explanation: Reversing a single node results in the same list

Example 3:

Input: head = 1 -> 2 -> 3, left = 1, right = 3 Output: 3 -> 2 -> 1 Explanation: The entire list is reversed