一、题目内容

二、题解

解法1：

思路

代码

public class Solution {
    public ListNode deleteDuplicates (ListNode head) {
        // write code here
        ListNode dummy = new ListNode(-1);
        dummy.next = head;
        ListNode next;
        ListNode pre = dummy,cur = head;
        while(cur!=null){
            next = cur.next;
            boolean hasRepeat = false;
            while(next!=null&&cur.val == next.val){
                next = next.next;
                pre.next = next;
                hasRepeat = true;
            }
            if(!hasRepeat){
                pre = cur;
            }
            cur = next;
        }
        return dummy.next;
    }
}