Day 2. Much easier. Getting the hang of it

day2/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day2"
+version = "0.1.0"

day2/Cargo.toml

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+[package]
+name = "day2"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day2/src/main.rs

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+use std::fs;
+
+fn main() {
+    let contents = fs::read_to_string("data.txt").expect("Failed to read file");
+    let lines = contents.trim().lines();
+    let turns: Vec<(&str, &str)> = lines
+        .map(|x| (x.get(0..1).unwrap(), x.get(2..3).unwrap()))
+        .collect();
+    let scores: Vec<usize> = turns.iter().map(|&x| score_part1(x)).collect();
+    let final_score_part1: usize = scores.iter().sum();
+    println!("Game 1 score: {final_score_part1}");
+
+    let scores2: Vec<usize> = turns.iter().map(|&x| score_part2(x)).collect();
+    let final_score_part2: usize = scores2.iter().sum();
+    println!("Game 2 score: {:?}", final_score_part2);
+}
+
+fn type_points(play: &str) -> usize {
+    match play {
+        "X" => 1,
+        "Y" => 2,
+        _ => 3,
+    }
+}
+
+fn win_points(turn: (&str, &str)) -> usize {
+    match turn {
+        ("C", "X") | ("A", "Y") | ("B", "Z") => 6, // win
+        ("A", "X") | ("B", "Y") | ("C", "Z") => 3, // draw
+        _ => 0,                                    // loss
+    }
+}
+
+fn score_part1(turn: (&str, &str)) -> usize {
+    win_points(turn) + type_points(turn.1)
+}
+
+fn score_part2(turn: (&str, &str)) -> usize {
+    let my_move: &str = match turn {
+        ("A", "X") | ("B", "Z") | ("C", "Y") => "Z", // lose to rock, win to paper, or draw with scissors -> I play scissors
+        ("A", "Y") | ("B", "X") | ("C", "Z") => "X", // draw with rock, lose to paper, win to scissors -> I play rock
+        _ => "Y",                                    // anything else -> I play paper
+    };
+
+    win_points((turn.0, my_move)) + type_points(my_move)
+}

day2/test.txt

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+A Y
+B X
+C Z