public void StressCn_Ctor2B()
{
// Use higher maxChoices values for a longer running test.
#if STRESS
const int maxChoices = 16;
#else
const int maxChoices = 5;
#endif
int counter = 0;
for (int choices = 0; choices <= maxChoices; ++choices)
{
for (int picks = 0; picks <= choices; ++picks)
{
long maxRows = Combinatoric.BinomialCoefficient(choices, picks);
for (int rank = 0; rank < maxRows; ++rank)
{
Combination row1 = new Combination(choices, picks, rank);
int[] source = new int[picks];
row1.CopyTo(source);
Combination row2 = new Combination(choices, source);
// verify that rank(unrank(x)) = x
Assert.AreEqual(rank, row1.Rank);
Assert.AreEqual(rank, row2.Rank);
++counter;
}
}
}
}
public void Unit_BinomialCoefficient2()
{
ResetCombinatoric();
long bc5 = Combinatoric.BinomialCoefficient(80, 3);
Assert.AreEqual(82160, bc5);
}
public void Unit_BinomialCoefficient3()
{
var bcTable = BuildPascalsTriangle();
for (int n = 0; n < bcTable.Count; ++n)
{
for (int k = 0; k < bcTable[n].Length; ++k)
{
long bc = Combinatoric.BinomialCoefficient(n, k);
Assert.AreEqual(bcTable[n][k], bc, "n=" + n + ", k=" + k);
}
}
}
public void Unit_BinomialCoefficient1()
{
ResetCombinatoric();
long bc1 = Combinatoric.BinomialCoefficient(1, -1);
Assert.AreEqual(0, bc1);
long bc2 = Combinatoric.BinomialCoefficient(1, 2);
Assert.AreEqual(0, bc2);
long bc3 = Combinatoric.BinomialCoefficient(65, 4);
Assert.AreEqual(677040, bc3);
long bc4 = Combinatoric.BinomialCoefficient(66, 33);
Assert.AreEqual(7219428434016265740, bc4);
}
public void Unit_BinomialCoefficient4()
{
var bcTable = BuildPascalsTriangle();
int n = bcTable.Count;
Assert.AreEqual(1, Combinatoric.BinomialCoefficient(n, 0));
for (int k = 1; k < n / 4; ++k)
{
long bc = Combinatoric.BinomialCoefficient(n, k);
long expected = bcTable[n - 1][k - 1] + bcTable[n - 1][k];
long actual = Combinatoric.BinomialCoefficient(n, k);
Assert.AreEqual(expected, actual, "k=" + k);
}
for (int k = (n * 3) / 4; k < n; ++k)
{
long bc = Combinatoric.BinomialCoefficient(n, k);
long expected = bcTable[n - 1][k - 1] + bcTable[n - 1][k];
long actual = Combinatoric.BinomialCoefficient(n, k);
Assert.AreEqual(expected, actual, "k=" + k);
}
}
public void Crash_BinomialCoefficient_Overflow()
{
long zz = Combinatoric.BinomialCoefficient(67, 34);
}
