fn life_support(field: bool, readings: &Vec<Vec<bool>>) -> u64 {

fn life_support(field: bool, readings: &[Vec<bool>]) -> u64 {

            (&remaining_2, &mut remaining_1)

            (remaining_2.as_slice(), &mut remaining_1)

            (&remaining_1, &mut remaining_2)

            (remaining_1.as_slice(), &mut remaining_2)