1、哨兵+双指针
import java.util.*; /* * public class ListNode { * int val; * ListNode next = null; * } */ public class Solution { /** * * @param head ListNode类 * @return ListNode类 */ public ListNode deleteDuplicates (ListNode head) { // write code here ListNode dummy = new ListNode(0); dummy.next = head; ListNode pre = dummy, cur = head; while (cur != null && cur.next != null) { if (cur.val == cur.next.val) { pre.next = cur.next; } else { pre = cur; } cur = cur.next; } return dummy.next; } }