Rotate List @LeetCode

package Level3;  
  
import Utility.ListNode;  
  
/** 
 *  
 * 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 S61 {  
  
    public static void main(String[] args) {  
        ListNode head = new ListNode(1);  
        ListNode n2 = new ListNode(2);  
        ListNode n3 = new ListNode(3);  
        ListNode n4 = new ListNode(4);  
        ListNode n5 = new ListNode(5);  
        head.next = n2;  
        n2.next = n3;  
        n3.next = n4;  
        n4.next = n5;  
          
        ListNode rotateHead = rotateRight(head, 2);  
        rotateHead.print();  
    }  
  
    public static ListNode rotateRight(ListNode head, int n) {  
        if(head == null){  
            return null;  
        }  
        ListNode back = head;  
        ListNode front = head;  
        ListNode end = head;  
          
        // 先把链表改为循环链表  
        while(front.next != null){  
            front = front.next;  
        }  
        end = front;        // 记录原尾节点  
        front.next = head;  // 形成环  
        front = head;       // 复原front指针  
          
        // 使得front在back前面n个距离  
        for(int i=0; i