vector < int > result = solve(a0, a1, a2, b0, b1, b2);
  for (ssize_t i = 0; i < result.size(); i++) {
    cout << result[i] << (i != result.size() - 1 ? " " : "");
  }

vector < int > result = solve(a0, a1, a2, b0, b1, b2);