删除顺序链表中重复的数 (一) leecode

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

 /**
  * Definition for singly-linked list.
  * public class ListNode {
  *     int val;
  *     ListNode next;
  *     ListNode(int x) {
  *         val = x;
  *         next = null;
  *     }
  * }
  */
 public class Solution {
     public ListNode deleteDuplicates(ListNode head) {

         if(head==null) return head;
         if(head.next==null) return head;

         ListNode pre=head;//save the pre to delete
         ListNode cur=head.next;
         while(cur!=null)
         {
             if(cur.val==pre.val)
             {

                 pre.next=cur.next;//删除cur节点
                 cur=cur.next; //处理下一个节点

             }
             else
             {
                 pre=pre.next;
                 cur=cur.next;

             }

         }

         return head;

     }
 }