Question

public static bool IsDivisible(double p, double n, double r, double k)
    {
        double x = p;
        double a = 0.0, b = 0.0, c = 0.0;
        while (x <= n)
        {
            a += Math.Floor(n / x);
            if (x <= r)
                b += Math.Floor(r / x);
            if (x <= k)
                c += Math.Floor(k / x);
            x *= p;
        }
        return a > b + c ? true : false;
    }

This above code checks if a nCr is divisible by a number p.k is n-r.
This function returns true if a particular nCr is divisible a number p.Can this be optimised further.

Answer 1

Are your inputs are always positive integers? If so, then you can improve performance using int instead of double and using integer division instead of floating point division. Then you also won’t need to call Math.Floor as integer division automatically truncates the result for you.

You can also simplify the last line to just this:

return a > b + c;