wheel-factorization.rs

fn gen_wheel(primes: Vec<u64>) -> Box<std::iter::Iterator<Item = u64>> {
    let mul = primes.iter().fold(1, |acc, x| acc * x);

    let stroke_left: Vec<_>= (2..(mul+1))
        .filter(|x| primes.iter().all(|&y| x % y != 0))
        .collect();

    let front_wheel: Vec<_> = vec![0].iter().chain(primes.iter())
        .zip(primes.iter().chain(stroke_left.iter().take(1)))
        .map(|(&x, &y)| y - x)
        .collect();

    let diff_wheel: Vec<_>= vec![1].iter().chain(stroke_left.iter())
        .zip(stroke_left.iter().chain(vec![mul+1].iter()))
        .map(|(&x, &y)| y - x)
        .collect();

    Box::new(front_wheel.into_iter().chain(diff_wheel.into_iter().cycle().skip(1)))
}

pub fn main() {
    let wheel = gen_wheel(vec![2,3]);

    for i in wheel.take(30) {
        println!("i = {}", i);
    }
}