Day 2, puzzle 2

src/bin/d2p1.rs

@@ -1,9 +1,32 @@
 use aoc22::day2;
 use aoc22::util;
 
+fn parse_choice(choice_char: char) -> day2::Choice {
+    match choice_char {
+        'A' => day2::Choice::Rock,
+        'B' => day2::Choice::Paper,
+        'C' => day2::Choice::Scissors,
+        'X' => day2::Choice::Rock,
+        'Y' => day2::Choice::Paper,
+        'Z' => day2::Choice::Scissors,
+        _ => panic!("Unknown choice {}", choice_char),
+    }
+}
+
+fn parse_round(round: &(char, char)) -> day2::Round {
+    day2::Round {
+        opponent: parse_choice(round.0),
+        own: parse_choice(round.1),
+    }
+}
+
 pub fn main() {
     let rounds = day2::parse_rounds(&util::parse_input());
 
-    let score = rounds.iter().map(day2::Round::score).sum::<u32>();
+    let score = rounds
+        .iter()
+        .map(parse_round)
+        .map(|round| round.score())
+        .sum::<u32>();
     println!("Total score is {}", score);
 }

src/bin/d2p2.rs

@@ -0,0 +1,47 @@
+use aoc22::day2::{self, Choice, Round, RoundResult};
+use aoc22::util;
+
+fn parse_choice(choice_char: char) -> Choice {
+    match choice_char {
+        'A' => Choice::Rock,
+        'B' => Choice::Paper,
+        'C' => Choice::Scissors,
+        _ => panic!("Unknown choice {}", choice_char),
+    }
+}
+
+fn parse_result(result_char: char) -> RoundResult {
+    match result_char {
+        'X' => RoundResult::Loss,
+        'Y' => RoundResult::Draw,
+        'Z' => RoundResult::Win,
+        _ => panic!("Unknown result {}", result_char),
+    }
+}
+
+fn parse_round(round: &(char, char)) -> Round {
+    let opponent = parse_choice(round.0);
+    let result = parse_result(round.1);
+    let (win, loss) = match opponent {
+        Choice::Rock => (Choice::Paper, Choice::Scissors),
+        Choice::Paper => (Choice::Scissors, Choice::Rock),
+        Choice::Scissors => (Choice::Rock, Choice::Paper),
+    };
+    let own = match result {
+        RoundResult::Win => win,
+        RoundResult::Draw => opponent,
+        RoundResult::Loss => loss,
+    };
+    Round { opponent, own }
+}
+
+pub fn main() {
+    let rounds = day2::parse_rounds(&util::parse_input());
+
+    let score = rounds
+        .iter()
+        .map(parse_round)
+        .map(|round| round.score())
+        .sum::<u32>();
+    println!("Total score is {}", score);
+}

src/day2.rs

@@ -1,4 +1,4 @@
-#[derive(PartialEq, Debug)]
+#[derive(PartialEq, Debug, Clone, Copy)]
 pub enum Choice {
     Rock,
     Paper,
@@ -15,10 +15,10 @@ impl Choice {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone, Copy)]
 pub struct Round {
-    opponent: Choice,
+    pub opponent: Choice,
-    own: Choice,
+    pub own: Choice,
 }
 
 pub enum RoundResult {
@@ -56,28 +56,16 @@ impl Round {
     }
 }
 
-pub fn parse_choice(choice_str: &str) -> Choice {
+pub fn parse_rounds(input: &String) -> Vec<(char, char)> {
-    match choice_str.chars().next().unwrap() {
-        'A' => Choice::Rock,
-        'B' => Choice::Paper,
-        'C' => Choice::Scissors,
-        'X' => Choice::Rock,
-        'Y' => Choice::Paper,
-        'Z' => Choice::Scissors,
-        _ => panic!("Unknown choice {}", choice_str),
-    }
-}
-
-pub fn parse_rounds(input: &String) -> Vec<Round> {
     let lines = input.lines();
     let mut rounds = Vec::new();
 
     for line in lines {
         let (opponent, own) = line.split_once(' ').unwrap();
-        rounds.push(Round {
+        rounds.push((
-            opponent: parse_choice(opponent),
+            opponent.chars().next().unwrap(),
-            own: parse_choice(own),
+            own.chars().next().unwrap(),
-        });
+        ));
     }
 
     rounds