#![allow(unused_variables)]
fn main() {
    use std::borrow::Cow;
    fn abs_all(input: &mut Cow<'_, [i32]>) {
        for i in 0..input.len() {
            let v = input[i];
            if v < 0 {
                input.to_mut()[i] = -v;
            }
        }
    }
    let slice = [0, 1, 2];
    let mut input = Cow::from(&slice[..]);
    abs_all(&mut input);
    let slice = [-1, 0, 1];
    let mut input = Cow::from(&slice[..]);
    abs_all(&mut input);
    let mut input = Cow::from(vec![- 1, 0, 1]);
    abs_all(&mut input);
}