题解 | #删除有序链表中重复的元素-I#

import java.util.*;

public class Solution {
    public ListNode deleteDuplicates (ListNode head) {
        if(head==null||head.next==null)
            return head;
        
        TreeSet<Integer> set = new TreeSet(){};
        ListNode p = head;
        ListNode dummy = new ListNode(0);
        ListNode q = dummy;

        while(p!=null){
            set.add(p.val);
            p=p.next;
        }
        for(Integer i: set){
            q.next = new ListNode(i);
            q=q.next;
        }

        return dummy.next;
    }
}