porting over AOC from previous years to a monorepo.

2022/days/02/src/part2.rs

@@ -0,0 +1,87 @@
+use crate::utilities::*;
+
+pub enum GameResult {
+    Win,
+    Loss,
+    Draw,
+}
+
+pub struct ResultStrategy {
+    pub elf: Play,
+    pub you: GameResult,
+}
+
+pub fn part2(input: &str) -> usize {
+    parse(input)
+        .iter()
+        .map(gen_strategy)
+        .map(|strat| calc_score(&strat))
+        .sum()
+}
+
+fn gen_strategy(input: &ResultStrategy) -> Strategy {
+    match input.you {
+        GameResult::Win => Strategy {
+            elf: input.elf,
+            you: gen_win(input.elf),
+        },
+        GameResult::Draw => Strategy {
+            elf: input.elf,
+            you: input.elf,
+        },
+        GameResult::Loss => Strategy {
+            elf: input.elf,
+            you: gen_loss(input.elf),
+        },
+    }
+}
+
+fn gen_win(opponent: Play) -> Play {
+    match opponent {
+        Play::Rock => Play::Paper,
+        Play::Paper => Play::Scissors,
+        Play::Scissors => Play::Rock,
+    }
+}
+
+fn gen_loss(opponent: Play) -> Play {
+    match opponent {
+        Play::Rock => Play::Scissors,
+        Play::Paper => Play::Rock,
+        Play::Scissors => Play::Paper,
+    }
+}
+
+pub fn parse(input: &str) -> Vec<ResultStrategy> {
+    input
+        .lines()
+        .map(|line| {
+            let elf = match line.as_bytes()[0] {
+                b'A' => Play::Rock,
+                b'B' => Play::Paper,
+                b'C' => Play::Scissors,
+                _ => panic!("your opponent not playing defined strategy!"),
+            };
+            let you = match line.as_bytes()[2] {
+                b'X' => GameResult::Loss,
+                b'Y' => GameResult::Draw,
+                b'Z' => GameResult::Win,
+                _ => panic!("you are not playing defined strategy!"),
+            };
+            ResultStrategy { elf, you }
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part2() {
+        let input = "A Y
+B X
+C Z";
+        assert_eq!(part2(input), 12);
+    }
+}