Anagram scoring in Rust

anagram.rs

#[derive(Debug,Clone)]
struct Match {
    c: u8,      // character
    pos: usize  // position
}

fn score(matches: &[Match]) -> usize {
    let l = matches.len();
    let mut s = 1;
    if l < 2 { return s }
    let c1 = &matches[0..(l-1)];
    let c2 = &matches[1..l];
    for n in 0..(l-1) {
        if (c2[n].pos as isize) - (c1[n].pos as isize) != 1 { s += 1 }
    }
    s
}

fn matches(s1: &[u8], s2: Vec<u8>, acc: Vec<Match>) -> Vec<Vec<Match>> {
    let l = s1.len(); 
    if l == 0 { return vec![acc] }
    let mut res: Vec<Vec<Match>> = vec![];
    let c = s1[0];
    for x in 0..s2.len() {
        if s2[x] == c {
            let mut ss2 = s2.clone();
            ss2[x] = 0;
            let mut acc = acc.clone();
            acc.push(Match { c: c, pos: x });
            res.append(&mut matches(&s1[1..l], ss2, acc));
        }
    }
    res
}

fn main() {
    let results = matches("cinematographer".as_bytes(), "megachiropteran".as_bytes().to_vec(), vec![]);
    let x = results.into_iter().map(|r| score(r.as_slice())).min().unwrap();
    println!("{:?}", x);
}