aoc 2022 day02

day02.rs

#[derive(Clone, Copy)]
enum Move {
    Rock,
    Paper,
    Scissors
}

impl Move {
    pub fn from(s: &str) -> Move{
        use Move::*;
        match s {
            "A" | "X" => Rock,
            "B" | "Y" => Paper,
            "C" | "Z" => Scissors,
            _ => unreachable!()
        }
    }
}

#[derive(Clone, Copy)]
enum End {
    Lose,
    Draw,
    Win
}

impl End {
    pub fn from(s: &str) -> End{
        use End::*;
        match s {
            "X" => Lose,
            "Y" => Draw,
            "Z" => Win,
            _ => unreachable!()
        }
    }
}

// part 2
fn main() {
    use Move::*;
    use End::*;
    let input = include_str!("day02_input.txt");

    let mut total_score = 0;
    for line in input.split('\n') {
        let mut split = line.split(' ');
        let (them, end) = (Move::from(split.next().unwrap()), End::from(split.next().unwrap()));
        let mut score = 0;

        let me = match (them, end) {
            (_, Draw) => them,
            (Rock, Lose) | (Paper, Win) => Scissors,
            (Rock, Win) | (Scissors, Lose)=> Paper,
            (Paper, Lose) | (Scissors, Win) => Rock,
        };

        match me {
            Rock => score += 1,
            Paper => score += 2,
            Scissors => score += 3,
        };

        match end {
            Lose => score += 0,
            Draw => score += 3,
            Win => score += 6,
        };
        total_score += score;
    }
    
    eprintln!("total score {total_score}");
}