题解 | #删除有序链表中重复的元素-I#

import java.util.*;
import java.util.stream.Collectors;

/*
 * 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
        ListNode result = new ListNode(-1);
        ListNode tmp = result;
        Set<Integer> set = new HashSet<>();
        while(head!=null){
            set.add(head.val);
            head = head.next;
        }
        List<Integer> ls = new ArrayList<>();
        for(Integer i:set){
            ls.add(i);
        }
        Collections.sort(ls);
        for(Integer i:ls){
            tmp.next = new ListNode(i);
            tmp = tmp.next;
        }
        return result.next;
    }
}