这要是tle我能接受，RE是什么鬼...

#include <cstdio>
#include <cstring>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <string>
#define maxn 50010
using namespace std;
long a[maxn];
long b[maxn];
int n, t;
int sum = 0;

int main() {
	cin >> t;
	while (t--) {
		scanf("%d",&n);
		for (int i = 0; i < n; i++) {
			scanf("%ld",&a[sum]);
			if (!b[a[sum]]) {
				b[a[sum]]++;
				sum++;
			}
		}
		for (int i = 0; i < sum; i++) {
			printf("%ld ",a[i]);
		}
		cout << endl;
		sum = 0;
		memset(b, 0, sizeof(b));
	}
	return 0;
}