Given a list, rotate the list to the right by k places, where k is non-negative.
Input: 1->2->3->4->5->null, 2
Output: 4->5->1->2->3->null
Input: 1->2->3->4->5->null, 6
Output: 5->1->2->3->4->null !!!
How do we get to the ith node in singly linked list? Get the total length. Then for loop until (len - k % len).
