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