Code

#include<bits/stdc++.h>
using namespace std;
unordered_map<int,bool>mp1; 
int a[100005];
int main(){
	int T;
	cin>>T;
	while(T--){
		int n;
		cin>>n;
		int cnt = 0;//多少个不重复的数字 
		mp1.clear();
		while(n--){
			int x;
			cin>>x;
			if(mp1[x]==0){
				a[++cnt] = x;
				mp1[x] = 1; 
			}
		}
		for(int i = 1;i<=cnt;i++){
			cout<<a[i]<<" ";
		}
		cout<<endl;
	} 
	return 0;
}