#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long a[n], b[n];
    for (long long i = 0; i < n; i++) cin >> a[i];
    for (long long i = 0; i < n; i++) cin >> b[i];
    sort(a, a + n);
    sort(b, b + n);
    for (long long i = 0; i < n; i++) {
      cout << a[i] << " ";
    }
    cout << endl;
    for (long long i = 0; i < n; i++) cout << b[i] << " ";
    cout << endl;
  }
  return 0;
}
