package leetcode._81_;

import leetcode.common.ListNode;

/**

* Definition for singly-linked list.

* public class ListNode {

* int val;

* ListNode next;

* ListNode(int x) { val = x; }

* }

*/

class Solution {

public ListNode deleteDuplicates(ListNode head) {

if (head == null) {

return null;

}

ListNode fakeHead = new ListNode(0);

fakeHead.next = head;

ListNode pre = fakeHead;

ListNode curr = head;

while (curr != null) {

while (curr.next != null && curr.val == curr.next.val) {

curr = curr.next;

}

if (pre.next == curr) { // 说明该次循环没有重复元素

pre = pre.next;

} else {

pre.next = curr.next;

}

curr = curr.next;

}

return fakeHead.next;

}

}