package factors

// MTC returns the multiplication table complexity of a radix n.
// This is an estimate of how difficult it is to learn a radix's
// multiplication table.
func MTC(n uint64) uint64 {
	mtc := uint64(0)
	for i := uint64(2); i <= n-2; i++ {
		mtc += n / gcd(i, n)
	}
	return mtc
}

func gcd(a, b uint64) uint64 {
	for b > 0 {
		a, b = b, a%b
	}
	return a
}