https://leetcode.com/problems/rotate-list/
Given the head of a linked list, rotate the list to the right by k places.
Example 1:
Input: head = [1,2,3,4,5], k = 2 Output: [4,5,1,2,3]
Constraints:
The number of nodes in the list is in the range [0, 500]. -100 <= Node.val <= 100 0 <= k <= 2 * 109