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.

只要一次删除的关系写对的话 都不是问题。

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode dummy = new ListNode(0);
        dummy.next= head;
        ListNode pre = dummy;
        ListNode pos = head;
        while(pos!=null)
        {
            int target = pos.val;
            pre=pos;
            while(pos!=null&&pos.val==target)
                {
                     pos=pos.next;
                }
                pre.next=pos;
                
        }
        return dummy.next;
    }
}