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|
static DAY: u8 = 2;
fn main() {
let input = advent::read_lines(DAY);
println!("{DAY}a: {}", game_score(&input, false));
println!("{DAY}b: {}", game_score(&input, true));
}
#[derive(PartialEq, Eq, Clone, Copy)]
enum Shape {
Rock,
Paper,
Scissors,
}
impl Shape {
fn score(&self) -> u32 {
match self {
Shape::Rock => 1,
Shape::Paper => 2,
Shape::Scissors => 3,
}
}
fn wins_against(&self) -> Shape {
match self {
Shape::Rock => Shape::Scissors,
Shape::Paper => Shape::Rock,
Shape::Scissors => Shape::Paper,
}
}
fn draws_against(&self) -> Shape {
*self
}
fn loses_against(&self) -> Shape {
match self {
Shape::Rock => Shape::Paper,
Shape::Paper => Shape::Scissors,
Shape::Scissors => Shape::Rock,
}
}
}
struct Round {
opponent: Shape,
you: Shape,
}
impl Round {
fn new(input: &str, result_indicator: bool) -> Round {
assert_eq!(input.len(), 3);
let chars : Vec<char> = input.chars().collect();
let opponent = match chars[0] {
'A' => Shape::Rock,
'B' => Shape::Paper,
'C' => Shape::Scissors,
_ => unreachable!(),
};
let you = if !result_indicator {
match chars[2] {
'X' => Shape::Rock,
'Y' => Shape::Paper,
'Z' => Shape::Scissors,
_ => unreachable!(),
}
} else {
match chars[2] {
'X' => opponent.wins_against(),
'Y' => opponent.draws_against(),
'Z' => opponent.loses_against(),
_ => unreachable!(),
}
};
Round { opponent, you }
}
fn outcome_score(&self) -> u32 {
if self.you.wins_against() == self.opponent {
6
} else if self.you.draws_against() == self.opponent {
3
} else if self.you.loses_against() == self.opponent {
0
} else {
unreachable!()
}
}
fn score(&self) -> u32 {
self.outcome_score() + self.you.score()
}
}
fn game_score(input: &[String], result_indicator: bool) -> u32 {
let rounds = input.iter()
.map(|x| Round::new(x, result_indicator))
.collect::<Vec<_>>();
rounds.iter()
.map(|x| x.score())
.sum()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let input = [
"A Y".to_string(),
"B X".to_string(),
"C Z".to_string(),
];
assert_eq!(game_score(&input, false), 15);
assert_eq!(game_score(&input, true), 12);
}
}
|
