/// <summary>
/// Count the number of possible combinations without repetition.
/// The order does not matter and each object can be chosen only once.
/// </summary>
/// <param name="n">Number of elements in the set.</param>
/// <param name="k">Number of elements to choose from the set. Each element is chosen at most once.</param>
/// <returns>Maximum number of combinations.</returns>
public static double Combinations(int n, int k)
{
return(SpecialFunctions.Binomial(n, k));
}
/// <summary>
/// Count the number of possible permutations (without repetition).
/// </summary>
/// <param name="n">Number of (distinguishable) elements in the set.</param>
/// <returns>Maximum number of permutations without repetition.</returns>
public static double Permutations(int n)
{
return(SpecialFunctions.Factorial(n));
}