import java.util.*;
/*
* public class ListNode {
* int val;
* ListNode next = null;
* }
*/
public class Solution {
public ListNode deleteDuplicates(ListNode head) {
if (head == null || head.next == null) {
return head;
}
ListNode newHead = new ListNode(0);
newHead.next = head;
ListNode cur = head;
ListNode last = newHead;
while (cur != null && cur.next != null) {
//如果相邻节点不相等，则当前节点赋值给新的的节点值
if (cur.val != cur.next.val) {
last = cur;
} else {
//如果相等，则next赋值删除后节点
while (cur.next != null && cur.val == cur.next.val) {
cur = cur.next;
}
//再赋值给新的节点
last.next = cur.next;
}
cur = cur.next;
}
return newHead.next;
}
}