day 2

2022/Cargo.toml

@@ -11,6 +11,10 @@ path = "src/lib.rs"
 name = "day1"
 path = "src/day1.rs"
 
+[[bin]]
+name = "day2"
+path = "src/day2.rs"
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]

2022/src/day1.rs

@@ -1,21 +1,5 @@
 const DATA: &'static str = include_str!("../data/day1.txt");
 
-// const DATA: &'static str = "1000
-// 2000
-// 3000
-
-// 4000
-
-// 5000
-// 6000
-
-// 7000
-// 8000
-// 9000
-
-// 10000
-// ";
-
 
 fn main() {
     let mut counts = DATA.trim()

2022/src/day2.rs

@@ -0,0 +1,108 @@
+use std::str::FromStr;
+
+
+const DATA: &'static str = include_str!("../data/day2.txt");
+// const DATA: &'static str = "
+// A Y
+// B X
+// C Z
+// ";
+
+
+enum RPS {
+    Rock = 1,
+    Paper = 2,
+    Scissors = 3,
+}
+impl FromStr for RPS {
+    type Err = ();
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "A" | "X" => Ok(Rock),
+            "B" | "Y" => Ok(Paper),
+            "C" | "Z" => Ok(Scissors),
+            _ => Err(())
+        }
+    }
+}
+
+
+enum Outcome {
+    Win = 6,
+    Loss = 0,
+    Draw = 3,
+}
+impl FromStr for Outcome {
+    type Err = ();
+    fn from_str(s: &str) -> Result<Self, ()> {
+        match s {
+            "X" => Ok(Loss),
+            "Y" => Ok(Draw),
+            "Z" => Ok(Win),
+            _ => Err(())
+        }
+    }
+}
+
+use RPS::*;
+use Outcome::*;
+
+
+fn compare(me: &RPS, them: &RPS) -> Outcome {
+    match (me, them) {
+        (Rock, Rock) => Draw,
+        (Rock, Paper) => Loss,
+        (Rock, Scissors) => Win,
+        (Paper, Rock) => Win,
+        (Paper, Paper) => Draw,
+        (Paper, Scissors) => Loss,
+        (Scissors, Rock) => Loss,
+        (Scissors, Paper) => Win,
+        (Scissors, Scissors) => Draw,
+    }
+}
+
+
+fn get_response(opponent: &RPS, outcome: &Outcome) -> RPS {
+    match (opponent, outcome) {
+        (Rock, Win) => Paper,
+        (Rock, Loss) => Scissors,
+        (Rock, Draw) => Rock,
+        (Paper, Win) => Scissors,
+        (Paper, Loss) => Rock,
+        (Paper, Draw) => Paper,
+        (Scissors, Win) => Rock,
+        (Scissors, Loss) => Paper,
+        (Scissors, Draw) => Scissors,
+    }
+}
+
+
+fn score(me: RPS, them: RPS) -> u64 {
+    let outcome = compare(&me, &them);
+    (me as u64) + (outcome as u64)
+}
+
+
+fn main() {
+    let mut total_1 = 0;
+    for pair in DATA.trim().split("\n") {
+        let mut it = pair.split(" ")
+            .map(|v| v.parse::<RPS>().unwrap());
+        let (them, me) = (it.next().unwrap(), it.next().unwrap());
+        total_1 += score(me, them);
+    }
+
+    println!("Part 1: {total_1}");
+
+    let mut total_2 = 0;
+    for pair in DATA.trim().split("\n") {
+        let mut it = pair.split(" ");
+        let them = it.next().unwrap().parse::<RPS>().unwrap();
+        let outcome = it.next().unwrap().parse::<Outcome>().unwrap();
+        let me = get_response(&them, &outcome);
+        total_2 += me as u64;
+        total_2 += outcome as u64
+    }
+    println!("Part 2: {total_2}");
+}