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 class Solution {
    /**
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    public ListNode deleteDuplicates (ListNode head) {
        // write code here
        ListNode pre = new ListNode(1001);
        pre.next = head;
        ListNode newList = pre;
        ListNode newListEnd = pre;
        while(head != null){
            pre = head;
            head = head.next;
            boolean move = false;
            while(head != null && pre.val == head.val){
                move = true;
                head = head.next;
            }
            if(move){
                pre = newListEnd;
                pre.next = head;
            }else{
                newListEnd.next = pre;
                newListEnd = pre;
            }
        }
        newList = newList.next;
        return newList;
    }
}