projecteuler.net/034/main.rs

fn ds(n: u32) -> Vec<u32> {
    let mut res = Vec::new();
    let mut a = n;
    while a > 0 {
        res.push(a % 10);
        a/=10;
    }
    res
}

fn fc(n: u32) -> u32 {
    if n == 0 { return 1; }
    return n * fc(n-1);
}

fn test(n: u32) -> bool {
    let d = ds(n);
    let mut sum = 0;
    for k in d {
        sum += fc(k);
    }
    return n == sum;
}


fn main() {
    let mut sum = 0;
    for n in 3..10_000_000 {
        if test(n) { 
            println!("{}", n);
            sum += n
        }
    }
    println!("sum: {}", sum);
}