Rotate List

public class Solution {
    public ListNode rotateRight(ListNode head, int n) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(head == null || n == 0){
            return head;
        }
        int len = 1;
        ListNode p = head;
        while(p.next != null){
            len ++;
            p = p.next;
        }
        p.next = head;

        int count = (len - n) % len;
        while(count < 0){
            count += len;
            count %= len;
        }
        int step = 0;
        while(step < count){
            p = p.next;
            step ++;
        }
        head = p.next;
        p.next = null;
        return head;
    }
}