Pass doors

pass_doors.rs

fn main() {
    let result: usize = pass_doors(8, 6);
    println!("Doors open: {}", result);
}

fn pass_doors(doors_num: usize, passes: usize) -> usize {
    let mut doors = vec![1; doors_num];
    let mut step: usize = 1;

    while step <= passes {
        for door in doors.iter_mut().step_by(step) {
            if *door == 1 {
                *door = 0
            } else {
                *door = 1;
            }
        }
        step += 1;
    }

    doors.iter().filter(|&door| *door == 0).count()
}