Leetcode 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.

Solution 1: simple LinkedList

 public class Solution {  
   public ListNode deleteDuplicates(ListNode head) {  
     if (head==null) return null;  
     ListNode x=head;  
     while (x.next!=null) {  
       if (x.val==x.next.val) x.next=x.next.next;  
       else x=x.next;  
     }  
     return head;  
   }  
 }