题解 | #删除有序链表中重复的元素-II#

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){
            return head;
        }
        ListNode tmp = new ListNode(1001);
        tmp.next = head;
        ListNode cur = head;
        ListNode pre = tmp;
        while(cur != null && cur.next!=null){
            if(cur.val != cur.next.val){
                cur = cur.next;
                pre = pre.next;
            }else{
                int num = cur.val;
                while(cur!=null&&cur.val==num){
                    cur = cur.next;
                }
                pre.next = cur;
                
                
            }
        }
        return tmp.next;
    }
}