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.

public class Solution {
    public ListNode rotateRight(ListNode head, int n) {
        if(head==null || n==0) return head;
        int len = 1;
        ListNode p = head;
        while(p.next!=null){
            p = p.next;
            len++;
        }
        p.next = head;
        for(int i=0;i<len -n%len;i++){
            p = p.next;
        }
        head = p.next;
        p.next= null;
        return head;
    }
}