#include<bits/stdc++.h>
using namespace std;
int main() {
    int T;
    cin >> T;
    unordered_set<int> b;
    while (T--) {
        int n, a;
        cin >> n;
        while (n--) {
            cin >> a;
            if (b.count(a) == 0) {
                cout << a << " ";
                b.insert(a);
            }
        }
         b.clear();
        cout << endl;
        
    }
    return 0;
}