1 /**
2 * Definition for singly-linked list.
3 * public class ListNode {
4 * int val;
5 * ListNode next;
6 * ListNode() {}
7 * ListNode(int val) { this.val = val; }
8 * ListNode(int val, ListNode next) { this.val = val; this.next = next; }
9 * }
10 */
11 class Solution {
12 public ListNode rotateRight(ListNode head, int k) {
13 // 针对空链表或单节点链表直接返回
14 if (k == 0 || head == null || head.next == null) {
15 return head;
16 }
17 // 初始链表长度
18 int n = 1;
19 // 计算链表长度
20 ListNode iter = head;
21 while (iter.next != null) {
22 iter = iter.next;
23 n++;
24 }
25 // 计算头结点平移长度
26 int add = n - k % n;
27 if (add == n) {
28 return head;
29 }
30 // 将链表头尾连接成环
31 iter.next = head;
32 // 找到新的尾节点
33 while (add > 0) {
34 iter = iter.next;
35 add --;
36 }
37 // 找到新的头节点
38 ListNode result = iter.next;
39 // 头尾断开
40 iter.next = null;
41 // 返回结果
42 return result;
43 }
44 }
