#删除有序链表中重复的元素-II#设立三个指针,前中后
删除有序链表中重复的元素-II
https://www.nowcoder.com/practice/71cef9f8b5564579bf7ed93fbe0b2024
import java.util.*; /* * public class ListNode { * int val; * ListNode next = null; * public ListNode(int val) { * this.val = val; * } * } */ public class Solution { /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param head ListNode类 * @return ListNode类 */ public ListNode deleteDuplicates (ListNode head) { // write code here if(head==null||head.next==null) return head; ListNode nhead=new ListNode(-1); ListNode q=nhead; ListNode p=head,tail=p,pre=null; if(p.val!=p.next.val) {q.next=p;q=q.next;} pre=p;p=p.next;tail=p.next; while(p.next!=null){ if(p.val!=pre.val&&p.val!=tail.val) { q.next=p; q=q.next; } pre=p; p=p.next; tail=p.next; } if(p.val!=pre.val) {q.next=p;q=q.next;} q.next=null; return nhead.next; } }