Day 2 - Part 1

Signed-off-by: Anthony Oteri <anthony.oteri@gmail.com>
2026-06-05 22:56:54 -04:00 · 2023-12-04 10:54:06 -05:00
parent cc95b8ce4f
commit a7b1299fe1
4 changed files with 266 additions and 0 deletions
@@ -0,0 +1,153 @@
+#![allow(dead_code)]
+
+#[derive(Debug, Clone)]
+struct Game {
+    id: usize,
+    bags: Vec<Bag>,
+}
+
+impl Game {
+    fn limit(&self, limit: &Bag) -> bool {
+        for bag in &self.bags {
+            if bag.red > limit.red || bag.green > limit.green || bag.blue > limit.blue {
+                println!("Discard game {} because of bag {:?}", self.id, bag);
+                return false;
+            }
+        }
+        true
+    }
+}
+
+#[derive(Debug, Clone, Default, Eq, PartialEq)]
+struct Bag {
+    red: u32,
+    green: u32,
+    blue: u32,
+}
+
+fn parse_input(input: &str) -> Vec<Game> {
+    let mut games = Vec::new();
+
+    for line in input.lines() {
+        let mut bags = Vec::new();
+
+        let (game_part, bags_part) = line.split_once(":").unwrap();
+
+        let game_id = game_part
+            .strip_prefix("Game ")
+            .unwrap()
+            .parse::<usize>()
+            .unwrap();
+
+        for bag_input in bags_part.split(';') {
+            let mut bag = Bag::default();
+
+            for color_cube in bag_input
+                .split(',')
+                .map(|s| s.trim())
+                .collect::<Vec<&str>>()
+            {
+                let (number, color) = color_cube.split_once(' ').unwrap();
+                match color {
+                    "red" => {
+                        bag.red = number.parse::<u32>().unwrap();
+                    }
+                    "green" => {
+                        bag.green = number.parse::<u32>().unwrap();
+                    }
+                    "blue" => {
+                        bag.blue = number.parse::<u32>().unwrap();
+                    }
+                    _ => panic!("unknown color"),
+                }
+            }
+            bags.push(bag);
+        }
+        games.push(Game { id: game_id, bags });
+    }
+
+    games
+}
+
+fn part_1(input: &str) -> usize {
+    let games = parse_input(input);
+
+    games
+        .iter()
+        .filter(|g| {
+            g.limit(&Bag {
+                red: 12,
+                green: 13,
+                blue: 14,
+            })
+        })
+        .map(|g| g.id)
+        .sum()
+}
+
+fn main() {
+    let input = include_str!("../input.txt");
+
+    println!("Part 1: {}", part_1(input));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_1_parse() {
+        let input = include_str!("../input_test_part1.txt");
+        let games = parse_input(input);
+
+        assert_eq!(games[0].id, 1);
+        assert_eq!(
+            games[0].bags,
+            vec![
+                Bag {
+                    blue: 3,
+                    red: 4,
+                    ..Bag::default()
+                },
+                Bag {
+                    green: 2,
+                    blue: 6,
+                    red: 1,
+                },
+                Bag {
+                    green: 2,
+                    ..Bag::default()
+                }
+            ]
+        );
+
+        assert_eq!(games[1].id, 2);
+        assert_eq!(games[2].id, 3);
+        assert_eq!(games[3].id, 4);
+        assert_eq!(games[4].id, 5);
+    }
+
+    #[test]
+    fn test_part_1_filter() {
+        let input = include_str!("../input_test_part1.txt");
+        let games = parse_input(input);
+
+        let bag = Bag {
+            red: 12,
+            green: 13,
+            blue: 14,
+        };
+        assert!(games[0].limit(&bag));
+        assert!(games[1].limit(&bag));
+        assert!(!games[2].limit(&bag));
+        assert!(!games[3].limit(&bag));
+        assert!(games[4].limit(&bag));
+    }
+
+    #[test]
+    fn test_part_1() {
+        let input = include_str!("../input_test_part1.txt");
+
+        assert_eq!(part_1(input), 8);
+    }
+}