69: Rotate linked list

Given an linked list and k, return a rotated linked list to the right on k steps

Example 1

Input:    head = 1 -> 2 -> 3 -> 4 -> null, k = 1

Output:   4 -> 1 -> 2 -> 3 -> null

Example 2

Input:    head = 1 -> 2 -> 3 -> 4 -> null, k = 1

Output:   1 -> 2 -> 3 -> 4 -> null,

Difficulty:Medium

Topic:Linked list

Problem #:69