[Rust] all subsets in vec

powerset.rs

fn powerset<T>(s: &[T]) -> Vec<Vec<&T>> {
    (0..2usize.pow(s.len() as u32))
        .map(|i| {
            s.iter()
                .enumerate()
                .filter(|&(t, _)| (i >> t) % 2 == 1)
                .map(|(_, e)| e)
                .collect()
        })
        .collect()
}