Rotate List

Given a list, rotate the list to the right by k places, where k is non-negative.

For example:
Given 1->2->3->4->5->NULL and k = 2,
return 4->5->1->2->3->NULL.

小细节容易写不好，cycle

public class Solution {

    public ListNode rotateRight(ListNode head, int k) {

        if(head ==null) return null;

        ListNode  tmp = head;

        int len =1;

        while(tmp.next!=null){

            tmp = tmp.next;

            len++;

        }

        tmp.next = head;

        k = k%len;

        for(int i=0; i<len-k; i++){

            tmp = tmp.next;

        }

        ListNode nh = tmp.next;

        tmp.next = null;

        return nh;

        

    }

}