Advent of Code Day 5

day05.rs

fn annihilate(polymer: &[u8], remove: u8) -> Vec<u8> {
    let mut result = Vec::new();
    for &c in polymer {
        if c == remove || c ^ 32 == remove {
            continue;
        }
        if result.is_empty() || result.last().unwrap() ^ c != 32 {
            result.push(c);
        } else {
            result.pop();
        }
    }
    result
}

fn main() {
    let polymer = include_bytes!("day05.in");
    let f = |c| annihilate(polymer, c).len();
    println!("{}", f(0));
    println!("{}", (b'a'..=b'z').map(f).min().unwrap());
}