Day2 Rust

day2/rust/.gitignore

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+target

day2/rust/Cargo.lock

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

day2/rust/Cargo.toml

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

day2/rust/src/main.rs

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+struct Game {
+    id: usize,
+    grabs: Vec<Grab>,
+}
+
+struct Grab {
+    cubes: Vec<Cube>,
+}
+
+struct Cube {
+    count: usize,
+    color: Color,
+}
+
+#[derive(Debug)]
+enum Color {
+    RED,
+    GREEN,
+    BLUE,
+    UNKNOWN,
+}
+
+fn main() {
+    let stdin = std::io::stdin();
+
+    let mut games: Vec<Game> = Vec::new();
+
+    // Read and parse input
+    for line in stdin.lines() {
+        let line = line.unwrap();
+
+        let (game_id_str, grab_strs) = line.split_once(":").unwrap();
+
+        let game_id = game_id_str.split_once(" ").unwrap().1.parse().unwrap();
+
+        let mut grabs = Vec::new();
+
+        for grab_str in grab_strs.split(";") {
+            let mut cubes = Vec::new();
+
+            for cube in grab_str.split(",").map(|str| str.trim()) {
+                let (count, color) = cube.split_once(' ').unwrap();
+
+                let count = count.parse().unwrap();
+                let color = match color {
+                    "red" => Color::RED,
+                    "green" => Color::GREEN,
+                    "blue" => Color::BLUE,
+                    _ => Color::UNKNOWN,
+                };
+
+                cubes.push(Cube { count, color })
+            }
+
+            grabs.push(Grab { cubes });
+        }
+
+        games.push(Game { id: game_id, grabs })
+    }
+
+    // Part 1
+    let red_cubes = 12;
+    let green_cubes = 13;
+    let blue_cubes = 14;
+    let mut part1 = 0;
+
+    for game in &games {
+        let mut possible = true;
+        for grab in &game.grabs {
+            for cube in &grab.cubes {
+                match cube.color {
+                    Color::RED => {
+                        if cube.count > red_cubes {
+                            possible = false;
+                            break;
+                        }
+                    }
+                    Color::GREEN => {
+                        if cube.count > green_cubes {
+                            possible = false;
+                            break;
+                        }
+                    }
+                    Color::BLUE => {
+                        if cube.count > blue_cubes {
+                            possible = false;
+                            break;
+                        }
+                    }
+                    Color::UNKNOWN => (),
+                }
+            }
+
+            if !possible {
+                break;
+            }
+        }
+
+        if possible {
+            part1 += game.id;
+        }
+    }
+
+    println!("{}", part1);
+
+    // Part 2
+    let mut part2 = 0;
+
+    for game in &games {
+        let mut min_reds = 0;
+        let mut min_greens = 0;
+        let mut min_blues = 0;
+
+        for grab in &game.grabs {
+            for cube in &grab.cubes {
+                match cube.color {
+                    Color::RED => {
+                        min_reds = std::cmp::max(min_reds, cube.count);
+                    }
+                    Color::GREEN => {
+                        min_greens = std::cmp::max(min_greens, cube.count);
+                    }
+                    Color::BLUE => {
+                        min_blues = std::cmp::max(min_blues, cube.count);
+                    }
+                    Color::UNKNOWN => (),
+                }
+            }
+        }
+
+        part2 += min_reds * min_greens * min_blues;
+    }
+
+    println!("{}", part2);
+}