code:

#include <cmath>
#include <cstdio>

#define sqr(x) ((x) * (x))

#define eps 1e-9

#define maxn 30

typedef double dbl;

int N;
dbl X[maxn], Y[maxn], R[maxn];
dbl AnsX, AnsY, AnsDX, AnsDY;

int DoIt( dbl A, dbl B, dbl C )
{
  dbl D = sqrt(A * A + B * B);
  if (D < eps)
    return 0;
  A /= D, B /= D, C /= D;
  for (int i = 0; i < N; i++)
    if (fabs(X[i] * A + Y[i] * B + C) > R[i] + eps)
      return 0;
  dbl A2 = B, B2 = -A, C2 = 0;
  AnsX = (C * B2 - C2 * B) /* (A * B2 - A2 * B)*/;
  AnsY = -(C * A2 - C2 * A) /* (B * A2 - B2 * A)*/;
  AnsDX = B, AnsDY = -A;
  return 1;
}

int Do2( dbl X1, dbl Y1, dbl X2, dbl Y2, dbl D )
{
  dbl A = Y1 - Y2;
  dbl B = X2 - X1;
  dbl D2 = sqrt(A * A + B * B);
  if (D2 < eps)
    return 0;
  A /= D2, B /= D2;
  dbl C = -(A * X1 + B * Y1);
  return DoIt(A, B, C + D) || DoIt(A, B, C - D);
}

int main( void )
{
  freopen("circles.in", "rt", stdin);
  freopen("circles.out", "wt", stdout);

  int K;
  scanf("%d", &K);
  for (int Test = 1; Test <= K; Test++)
  {
    scanf("%d", &N);
    for (int i = 0; i < N; i++)
      scanf("%lf%lf%lf", &X[i], &Y[i], &R[i]);
    int f = 0;

    for (int i = 0; i < N && !f; i++)
      if (DoIt(1, 0, -X[i]))
        f = 1;
    for (int i = 0; i < N && !f; i++)
      for (int j = 0; j < N && !f; j++)
        if (DoIt(Y[i] - Y[j], X[j] - X[i], -((Y[i] - Y[j]) * X[i] + (X[j] - X[i]) * Y[i])))
          f = 1;
    for (int i = 0; i < N && !f; i++)
      for (int j = 0; j < N && !f; j++)
        if (R[i] <= R[j] + eps)
        {
          dbl R1 = fabs(R[j] - R[i]);
          dbl R2 = fabs(R[j] + R[i]);
          dbl D2 = sqr(X[i] - X[j]) + sqr(Y[i] - Y[j]);
          dbl D = sqrt(D2);
          dbl cosa = (X[j] - X[i]) / D;
          dbl sina = (Y[j] - Y[i]) / D;
          if (D2 >= R1 * R1 - eps && D2 > eps)
          {
            dbl A2 = fabs(D2 - R1 * R1);
            dbl A1 = sqrt(A2);
            dbl TX = (A2 - R1 * R1 + D2) / (2 * D);
            dbl TY1 = sqrt(fabs(A2 - TX * TX));
            dbl TY2 = -TY1;
            dbl RX1 = cosa * TX - sina * TY1 + X[i];
            dbl RY1 = sina * TX + cosa * TY1 + Y[i];
            dbl RX2 = cosa * TX - sina * TY2 + X[i];
            dbl RY2 = sina * TX + cosa * TY2 + Y[i];
            if (Do2(X[i], Y[i], RX1, RY1, R[i]) || Do2(X[i], Y[i], RX2, RY2, R[i]))
            {
              f = 1;
              break;
            }
          }
          if (D2 >= R2 * R2 - eps && D2 > eps)
          {
            dbl A2 = fabs(D2 - R2 * R2);
            dbl A1 = sqrt(A2);
            dbl TX = (A2 - R2 * R2 + D2) / (2 * D);
            dbl TY1 = sqrt(fabs(A2 - TX * TX));
            dbl TY2 = -TY1;
            dbl RX1 = cosa * TX - sina * TY1 + X[i];
            dbl RY1 = sina * TX + cosa * TY1 + Y[i];
            dbl RX2 = cosa * TX - sina * TY2 + X[i];
            dbl RY2 = sina * TX + cosa * TY2 + Y[i];
            if (Do2(X[i], Y[i], RX1, RY1, R[i]) || Do2(X[i], Y[i], RX2, RY2, R[i]))
            {
              f = 1;
              break;
            }
          }
        }

    if (f)
      printf("Test case %d: The circles are on (%.20lf, %.20lf) + (%.20lf, %.20lf) * t\n", Test, AnsX, AnsY, AnsDX, AnsDY);
    else
      printf("Test case %d: There are no suitable straight lines.\n", Test);
  }

  return 0;
}