不重复数字

# include<stdio.h>
# include<algorithm>
# include<iostream>
# include<set>
using namespace std;
int main(){
	int t,n,r;
	set<int>s;
	scanf("%d",&t);
	while(t--){
		s.clear();
		scanf("%d",&n);
		scanf("%d",&r);
		printf("%d",r);
		s.insert(r);
		for(int i=2;i<=n;i++){
			scanf("%d",&r);
			if(s.count(r)==0){
				printf(" %d",r);
				s.insert(r);
			}
		}
		printf("\n");
	}
	return 0;
}