/**

  * Definition for ListNode

  * public class ListNode {

  *     int val;

  *     ListNode next;

  *     ListNode(int x) {

  *         val = x;

  *         next = null;

  *     }

  * }

  */

 public class Solution {

     /*

      * @param head: head is the head of the linked list

      * @return: head of linked list

      */

     public ListNode deleteDuplicates(ListNode head) {

         // write your code here

         if(head == null) {

             return null;

         }

         //新建一个链表，h节点作为头节点，将链表的第一个值赋给它

         ListNode h = new ListNode(head.val);

         ListNode p = h;

         while(head.next != null) {

             head = head.next;

             if(head.val != p.val) {

                 ListNode node = new ListNode(head.val);

                 p.next = node;

                 p = p.next;

             }

         }

         return h;

     }

 }