public static FracClass computeAnswer(bool[] gondalas)
{
FracClass sum = 0;
WheelLargeSlow dp = new WheelLargeSlow(gondalas);
for (int i = 0; i < gondalas.Length; ++i)
{
if (gondalas[i])
continue;
int nextI = (i + 1) % gondalas.Length;
FracClass probIFilledLast = dp.P(nextI, i);
FracClass expValue = dp.E(nextI, i);
#if USE_DOUBLE
expValue += (double) (gondalas.Length + 1) / 2d;
#else
expValue += new FracClass(gondalas.Length + 1, 2);
#endif
sum += probIFilledLast * expValue;
Preconditions.checkState(sum >= 0);
}
return sum;
}
public void TestP()
{
bool[] gondolas = new bool[] { false, false, true, false, true };
WheelLargeSlow dp = new WheelLargeSlow(gondolas);
Assert.AreEqual((double)new BigFraction(12, 64), (double)dp.P(0, 3));
gondolas = new bool[] { false, true, false, true, false };
dp = new WheelLargeSlow(gondolas);
Assert.AreEqual((double)new BigFraction(12, 64), (double)dp.P(4, 2));
}
public void TestCompare()
{
int trials = 100;
Random r = new Random(3);
for(int t = 0; t < trials; ++t)
{
bool[] gondolas = new bool[7];
for(int i = 0; i < gondolas.Length; ++i)
{
gondolas[i] = r.Next(2) == 1 ? true : false;
}
int start = r.Next(0, gondolas.Length);
int stop = r.Next(0, gondolas.Length);
gondolas[start] = false;
gondolas[stop] = false;
WheelLargeSlow dp = new WheelLargeSlow(gondolas);
Logger.LogTrace("Gondolas {} start {} stop {}", gondolas.ToCommaString(), start, stop);
Assert.AreEqual((double)WheelBruteForce.P_bruteForce(gondolas, start, stop),
(double)dp.P(start, stop), 1e-9, gondolas.ToCommaString());
}
}
