Copy from github.com with solutions for days 1+2

2022/day02-part2/src/main.rs

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+// Use a custom type to identify the different shapes that can be used in the game.
+#[derive(Copy, Clone)]
+enum Shape {
+    Rock,
+    Paper,
+    Scissors,
+}
+
+#[derive(Copy, Clone)]
+enum Outcome {
+    Loss,
+    Draw,
+    Win,
+}
+
+// Allows us to use the shapes without the Shape:: prefix.
+use Shape::*;
+use Outcome::*;
+
+fn main() {
+    // Use command line arguments to specify the input filename.
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() < 2 {
+        panic!("Usage: ./main <input-file>\nNo input file provided. Exiting.");
+    }
+
+    // Next, read the contents of the input file into a string for easier processing.
+    let input = std::fs::read_to_string(&args[1]).expect("Error opening file");
+    // Line-by-line processing is easiest.
+    let mut input = input.lines();
+
+    // --- TASK BEGIN ---
+    let mut total_score = 0;
+
+    while let Some(line) = input.next() {
+        // Translate the line's first character into its respective shape.
+        let opponent_shape = match line.chars().nth(0) {
+            Some('A') => Rock,
+            Some('B') => Paper,
+            Some('C') => Scissors,
+            _ => { panic!("Unexpected left character."); }
+        };
+
+        // Translate the line's second character into its respective shape.
+        let player_outcome = match line.chars().nth(2) {
+            Some('X') => Loss,
+            Some('Y') => Draw,
+            Some('Z') => Win,
+            _ => { panic!("Unexpected right character."); }
+        };
+
+        // Determine the player_shape from the predetermined outcome.
+        let player_shape = match (player_outcome, opponent_shape) {
+            (Loss, Rock    ) => Scissors,
+            (Loss, Paper   ) => Rock,
+            (Loss, Scissors) => Paper,
+            (Draw, Rock    ) => Rock,
+            (Draw, Paper   ) => Paper,
+            (Draw, Scissors) => Scissors,
+            (Win , Rock    ) => Paper,
+            (Win , Paper   ) => Scissors,
+            (Win , Scissors) => Rock,
+        };
+
+        // Add the score for the matchup (win/loss/draw) to the total score.
+        total_score += match (player_shape, opponent_shape) {
+            (Rock    , Rock    ) => 3,
+            (Rock    , Paper   ) => 0,
+            (Rock    , Scissors) => 6,
+            (Paper   , Rock    ) => 6,
+            (Paper   , Paper   ) => 3,
+            (Paper   , Scissors) => 0,
+            (Scissors, Rock    ) => 0,
+            (Scissors, Paper   ) => 6,
+            (Scissors, Scissors) => 3,
+        };
+
+        // Add the score of the player's shape to the total score.
+        total_score += match player_shape {
+            Rock     => 1,
+            Paper    => 2,
+            Scissors => 3,
+        };
+    }
+
+    println!("Total score: {}", total_score);
+}
+