Module malachite_base::num::arithmetic::binomial_coefficient

Traits for computing the binomial coefficient of two numbers. There is a trait whose implementations panic if the result cannot be represented, and a checked trait whose implementations return None in that case: BinomialCoefficient and CheckedBinomialCoefficient.

binomial_coefficient

use malachite_base::num::arithmetic::traits::BinomialCoefficient;

assert_eq!(u8::binomial_coefficient(3, 0), 1);
assert_eq!(u8::binomial_coefficient(3, 1), 3);
assert_eq!(u8::binomial_coefficient(3, 2), 3);
assert_eq!(u8::binomial_coefficient(3, 3), 1);
assert_eq!(u8::binomial_coefficient(10, 5), 252);

assert_eq!(i8::binomial_coefficient(-3, 0), 1);
assert_eq!(i8::binomial_coefficient(-3, 1), -3);
assert_eq!(i8::binomial_coefficient(-3, 2), 6);
assert_eq!(i8::binomial_coefficient(-3, 3), -10);

checked_binomial_coefficient

use malachite_base::num::arithmetic::traits::CheckedBinomialCoefficient;

assert_eq!(u8::checked_binomial_coefficient(3, 0), Some(1));
assert_eq!(u8::checked_binomial_coefficient(3, 1), Some(3));
assert_eq!(u8::checked_binomial_coefficient(3, 2), Some(3));
assert_eq!(u8::checked_binomial_coefficient(3, 3), Some(1));
assert_eq!(u8::checked_binomial_coefficient(10, 5), Some(252));
assert_eq!(u8::checked_binomial_coefficient(11, 5), None);

assert_eq!(i8::checked_binomial_coefficient(-3, 0), Some(1));
assert_eq!(i8::checked_binomial_coefficient(-3, 1), Some(-3));
assert_eq!(i8::checked_binomial_coefficient(-3, 2), Some(6));
assert_eq!(i8::checked_binomial_coefficient(-3, 3), Some(-10));
assert_eq!(i8::checked_binomial_coefficient(-3, -3), None);
assert_eq!(i8::checked_binomial_coefficient(11, 5), None);