Rotate List

/**
* Definition for singly-linked list.
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int x) {
*         val = x;
*         next = null;
*     }
* }
*/
public class Solution {
public ListNode rotateRight(ListNode head, int n) {
if(head == null) {
return null;
}
ListNode slow = head, fast = head;
for(int i = 0; i < n; i++) {
fast = fast.next;
if(fast == null) {
fast = head;
}
}
while(fast.next != null) {
slow = slow.next;
fast = fast.next;
}
fast.next = head;
head = slow.next;
slow.next = null;
return head;
}
}