class Solution {
public ListNode rotateRight(ListNode head, int k) {
if (k == 0 || head == null || head.next == null) {
return head;
}
int n = 1; //链表长度
ListNode iter = head;
while (iter.next != null) {
iter = iter.next;
n++;
}
if (k % n == 0) {
return head;
}
int add = n - k % n;
iter.next = head; //成环
while (add-- != 0) {
iter = iter.next;
}
ListNode res = iter.next;
iter.next = null;
return res;
}
}