package com.q0082;

import com.q0086_partition_list.ListNode;

/**

* https://leetcode-cn.com/problems/remove-duplicates-from-sorted-list-ii/

* 82. 删除排序链表中的重复元素 II

*/

public class Solution {

public ListNode deleteDuplicates(ListNode head) {

if (head == null || head.next == null) {

return head;

}

ListNode dummyHead = new ListNode(0);

dummyHead.next = head;

ListNode pre = dummyHead;

ListNode cur = pre.next;

//pre c

// p p

// 0-->1-->1-->1-->1-->2

//pre c p

//0-->1-->4-->2

while (cur != null) {

int num = 0;

ListNode p = cur;

while (p != null && p.val == cur.val) {

num++;

p = p.next;

}

if (num > 1) {

pre.next = p;

}else {

pre = cur;

}

cur = p;

}

return dummyHead.next;

}

}