Day 2, Part 1 & 2

src/bin/d2.rs

@@ -0,0 +1,47 @@
+const INPUT: &str = include_str!("../input/d2.txt");
+
+fn main() -> anyhow::Result<()> {
+    let score_p1 = INPUT
+        .as_bytes()
+        .chunks(4)
+        .map(|l| play_points(l[0] as char, l[2] as char))
+        .sum::<usize>();
+    println!("{score_p1:?}");
+    let score_p2 = INPUT
+        .as_bytes()
+        .chunks(4)
+        .map(|l| result_points(l[0] as char, l[2] as char))
+        .sum::<usize>();
+    println!("{score_p2:?}");
+    anyhow::Ok(())
+}
+
+fn play_points(opponent: char, player: char) -> usize {
+    match (opponent, player) {
+        ('A', 'X') => 4,
+        ('A', 'Y') => 8,
+        ('A', 'Z') => 3,
+        ('B', 'X') => 1,
+        ('B', 'Y') => 5,
+        ('B', 'Z') => 9,
+        ('C', 'X') => 7,
+        ('C', 'Y') => 2,
+        ('C', 'Z') => 6,
+        _ => unreachable!(),
+    }
+}
+
+fn result_points(opponent: char, result: char) -> usize {
+    match (opponent, result) {
+        ('A', 'X') => 3,
+        ('A', 'Y') => 4,
+        ('A', 'Z') => 8,
+        ('B', 'X') => 1,
+        ('B', 'Y') => 5,
+        ('B', 'Z') => 9,
+        ('C', 'X') => 2,
+        ('C', 'Y') => 6,
+        ('C', 'Z') => 7,
+        _ => unreachable!(),
+    }
+}