#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
long long pm(long long x, long long n) {
  long long result = 1;
  while (n > 0) {
    if (n % 2 == 1) result = ((result % mod) * (x % mod)) % mod;
    x = ((x % mod) * (x % mod)) % mod;
    n /= 2;
  }
  return result;
}
long long p(long long x, long long n) {
  long long result = 1;
  while (n > 0) {
    if (n % 2 == 1) result = result * x;
    x = x * x;
    n /= 2;
  }
  return result;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long ncr(long long n, long long r) {
  long long p = 1, k = 1;
  if (n - r < r) r = n - r;
  if (r != 0) {
    while (r != 0) {
      p *= n;
      k *= r;
      long long temp = gcd(p, k);
      p /= temp;
      k /= temp;
      n--;
      r--;
    }
  } else
    p = 1;
  return p;
}
long long factorial[200000 + 1];
void fact(long long n) {
  factorial[0] = 1;
  factorial[1] = 1;
  for (int i = 2; i < n + 1; i++)
    factorial[i] = (i * factorial[i - 1] % mod) % mod;
}
long long d, coeff1, coeff2;
void euclid(long long a, long long b) {
  if (b == 0) {
    d = a;
    coeff1 = 1;
    coeff2 = 0;
  } else {
    euclid(b, a % b);
    long long temp = coeff1;
    coeff1 = coeff2;
    coeff2 = temp - (a / b) * (coeff2);
  }
}
long long modinv(long long a) {
  euclid(a, mod);
  return (coeff1 % mod + mod) % mod;
}
long long prime[1000001] = {};
void sieve(long long n) {
  prime[0] = 1;
  prime[1] = 1;
  for (long long i = 2; i * i <= n; i++) {
    if (prime[i] == 0) {
      for (long long j = i * i; j <= n; j += i) prime[j] = 1;
    }
  }
}
int main() {
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    long long x[n];
    long long y[n];
    for (int i = 0; i < n; i++) cin >> x[i];
    for (int i = 0; i < n; i++) cin >> y[i];
    sort(x, x + n);
    sort(y, y + n);
    for (int i = 0; i < n; i++) cout << x[i] << " ";
    cout << "\n";
    for (int i = 0; i < n; i++) cout << y[i] << " ";
    cout << "\n";
  }
  return 0;
}
