Leetcode-Rotate List

 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) {
 7  *         val = x;
 8  *         next = null;
 9  *     }
10  * }
11  */
12 public class Solution {
13     public ListNode rotateRight(ListNode head, int n) {
14         if (head==null || head.next==null) return head;
15     
16         ListNode end = null;
17         int len = 1;
18         end = head;
19         while (end.next!=null){
20             end = end.next;
21             len++;
22         }
23         end.next = head;
24         int step = len - n%len;
25         int index = 1;
26         end = head;
27         while (index<step){
28             end = end.next;
29             index++;
30         }
31         head = end.next;
32         end.next = null;
33         return head;              
34     }
35 }