Rotate Linked List

RotateLinkedList.java

/**
 * 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 || n == 0 || head.next == null) return head;
        
        ListNode end = head;
        int length = 1;
        while (end.next != null){
            end = end.next;
            length++;
        }
        n = n%length;
        if (n == 0) return head;
        
        //make circular
        end.next = head;
        
        for (int i = 0; i < length - n; i++){
            end = end.next;
        }
        head = end.next;
        end.next = null;
        
        return head;
        
    }
}