fn sort_with_index_by<T, U: Ord, F: FnMut(usize, &T) -> U>(slice: &mut [T], mut f: F) {
    let mut range: Vec<_> = (0..slice.len()).collect();

    range.sort_by_key(|&x| f(x, &slice[x]));

    fn sort_chain<T>(o: usize, n: usize, slice: &mut [T], range: &mut [usize]) {
        let i = range[n];

        if i == o {
            slice.swap(o, n);
            range.swap(o, n);
            return;
        }

        if i != n {
            sort_chain(o, i, slice, range);
            slice.swap(o, n);
            range.swap(o, n);
        }
    }

    for i in 0..slice.len() {
        if range[i] != i {
            sort_chain(i, i, slice, &mut range);
        }
    }
}

fn main() {
    let a = [1, 0, 3, 4, 2];
    let mut b = ['a', 'b', 'c', 'd', 'e'];

    let mut i: Vec<_> = b.iter().cloned().enumerate().collect();
    i.sort_by_key(|&(i, _)| a[i]);
    let (_, t): (Vec<_>, Vec<_>) = i.into_iter().unzip();

    println!("{:?}", t);

    sort_with_index_by(&mut b, |i, _| a[i]);

    println!("{:?}", b);
}