pub fn crt(r1: u64, m1: u64, r2: u64, m2: u64) -> Option<(u64, u64)>
Chinese Remainder: solve x ≡ r1 (mod m1), x ≡ r2 (mod m2) for coprime moduli, returning (x, m1·m2). None if the moduli are not coprime.
x ≡ r1 (mod m1)
x ≡ r2 (mod m2)
(x, m1·m2)
None