Remove Duplicates from Sorted List II

 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) {
 7  *         val = x;
 8  *         next = null;
 9  *     }
10  * }
11  */
12 public class Solution {
13     public ListNode deleteDuplicates(ListNode head) {
14         ListNode header = new ListNode(Integer.MAX_VALUE);
15         header.next = head;
16         ListNode cur = header, pre = header.next;
17         header.next = null;
18         while(pre != null){
19             ListNode tmp = pre;
20             while(pre != null && pre.val == tmp.val) pre = pre.next;
21             if(tmp.next == pre){
22                 cur.next = tmp;
23                 cur = cur.next;
24                 cur.next = null;
25             }
26         }
27         return header.next;
28     }
29 }