DEFCON 2025 puzzle 3 solvinator

/*
Red    = 01
Green  = 00
Blue   = 10
Yellow = 11
*/

const COLOR_ORDER: &str = "grby";

fn bool_array_to_char(byte: [bool; 8]) -> char {
    let mut b = 0u8;
    for i in 0..8 {
        b |= u8::from(byte[i]) << (7 - i % 8);
    }
    return char::from(b)
}

fn main() {
    let grid = [
        "rrryrbbg",
        "rbgrryrg",
        "gbggrbbr",
        "rygygbgg",
        "gybggybg",
        "gbyrgyrr",
        "gyrggbby",
        "gybggyyy"
    ];

    fn parse_color(color: char) -> usize {
        COLOR_ORDER.find(color).unwrap_or(0)
    }

    fn do_that(offset: usize, line: &str) -> [bool; 8] {
        let mut byte: [bool; 8] = [false; 8];
        let mut byte_i = 0;
        for i in 0..=3 {
            let col_value = parse_color(line.chars().nth(i + offset).unwrap_or(' '));

            byte[byte_i] = match col_value {
                0 => false,
                1 => false,
                2 => true,
                3 => true,
                _ => false,
            };

            byte_i += 1;

            byte[byte_i] = match col_value {
                0 => false,
                1 => true,
                2 => false,
                3 => true,
                _ => false,
            };

            byte_i += 1;
        }

        return byte
    }

    for line in grid.iter() {
        print!("{}", bool_array_to_char(do_that(0, line)));
        print!("{}", bool_array_to_char(do_that(4, line)));
    }

    println!("");
}