题解 | 不重复数字

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int T = in.nextInt();
        while(T-->0){
            HashSet<Integer> set = new HashSet<>();
            StringBuilder s = new StringBuilder();//转字符串输出不然大量IO操作会超时
            int n = in.nextInt();
            for(int i=0;i<n;i++){
                int a = in.nextInt();
                if(!set.contains(a)){
                    set.add(a);
                    s.append(a+" ");
                }
            }
            System.out.println(s);
        }
    }
}