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.

  

可以用一个指针，也可以用两个指针来完成

/** * 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){            return null;        }                ListNode cur = head;        while(cur.next != null){            if(cur.val == cur.next.val){                cur.next = cur.next.next;            }else{                cur = cur.next;            }        }        return head;            }}

 

 

/** * 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) return head;                ListNode pre = head;        ListNode cur = head.next;                while(cur != null && pre != null){                        if(cur.val == pre.val){                pre.next = cur.next;                cur = cur.next;                            }else{                pre = pre.next;                cur = cur.next;            }        }        return head;                    }}