check if two vectiors are a permutation of the same set

permutations_test.rs

use std::cmp::PartialEq;

fn is_perm<T: PartialEq>(xs: &Vec<T>, ys: &Vec<T>) -> bool {
    let mut ok = xs.len() == ys.len();
    let mut ws: Vec<&T> = xs.iter().collect();
    let mut zs: Vec<&T> = ys.iter().collect();
    while ok && ws.len() != 0 {
        let (ok0, i) = exists(&zs, &ws[0]);
        ok = ok0;
        if ok0 {
            ws.remove(0);
            zs.remove(i);
        }
    }
    ok
}

fn exists<T: PartialEq>(ys: &Vec<T>, v: &T) -> (bool, usize) {
    let mut ok = false;
    let mut i: usize = 0;
    while !ok && i != ys.len() {
        ok = &ys[i] == v;
        if !ok {
            i = i + 1;
        }
    }
    (ok, i)
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_is_perm() {
        let ts = vec![
            (vec![0, 2, 1], vec![0, 1, 2], true),
            (vec![0], vec![2], false),
            (vec![], vec![1], false),
            (vec![], vec![], true),
            (vec![0, 0, 1], vec![0, 1, 1], false),
        ];
        for j in ts.iter() {
            let ok = super::is_perm(&j.0, &j.1);
            assert_eq!(j.2, ok);
        }
    }
}