Function num_bigint_dig::algorithms::extended_gcd

pub fn extended_gcd(
    a_in: Cow<BigUint>, 
    b_in: Cow<BigUint>, 
    extended: bool
) -> (BigInt, Option<BigInt>, Option<BigInt>)

Uses the lehemer algorithm. Based on https://github.com/golang/go/blob/master/src/math/big/int.go#L612 If extended is set, the Bezout coefficients are calculated, otherwise they are None.