fast-fibonacci

Quickly find nth fibonacci number, with modulo.

fn fib_with_mod(n: u64, modulo: u64) -> u64

Uses linear recurrence to find nth fibonacci number with modulo. O(log(n))

fn bigfib_with_mod(n: &BigUint, modulo: &BigUint) -> BigUint

BigUint version of fib_with_mod. Uses linear recurrence to find nth fibonacci number with modulo. O(log(n))