projecteuler.net/052/main.rs

use std::collections::HashMap;
fn get_hs(n: u32) -> HashMap<u8, u32> {
    let mut nn = n;
    let mut res = HashMap::<u8, u32>::new();
    while nn > 0 {
        let c = (nn%10) as u8;
        if res.contains_key(&c) {
            res.insert(c, res[&c] + 1);
        } else {
            res.insert(c, 1);
        }
        nn /= 10;
    }
    return res;
}


fn test(n: u32) -> bool {
    let hm = get_hs(n);
    for i in 2..=6 {
        let m = n * i;
        let hmi = get_hs(m);
        if hmi != hm {
            return false;
        }
    }
    return true;
}

fn main() {
    for i in 1..999999 {
    
        if test(i) {
            println!("{}", i);
            break;
        }
    }

}