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;
}