Function Combinations

math/binomialcoefficient.go:22–35

C is Binomial Coefficient function This function returns C(n, k) for given n and k

(n int, k int)

// C is Binomial Coefficient function
// This function returns C(n, k) for given n and k
func Combinations(n int, k int) (int, error) {
	if n < 0 || k < 0 {
		return -1, ErrPosArgsOnly
	}
	if k > (n - k) {
		k = n - k
	}
	res := 1
	for i := 0; i < k; i++ {
		res *= (n - i)
		res /= (i + 1)
	}
	return res, nil
}