#include<bits/stdc++.h>
#include <vector>
using namespace std;
unordered_set<int>s;int T,n,a;
int main(){
    cin>>T;
    for (int i=0; i<T;++i) {
        cin>>n;
        for (int j=0;j<n;++j) {
            cin>>a;
            if (s.count(a)==0) {
                cout<<a<<' ';s.insert(a);
            }
        }
        cout<<endl;s.clear();
    }
    return 0;
}