83. Remove Duplicates from Sorted List

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

代码如下：

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

       ListNode heads=head;
         ListNode p=head.next;
         while(p!=null)
         {
             if(p.val==heads.val)
             {
                 p=p.next;
                 heads.next=p;
             }
             else
             heads=heads.next;
         }
         return head;
     }
 }