day2 solution 1

1 files changed, 78 insertions, 0 deletions

diff --git a/src/bin/day2.rs b/src/bin/day2.rs
new file mode 100644
index 0000000..1f4a1d3
--- /dev/null
+++ b/src/bin/day2.rs
@@ -0,0 +1,78 @@
+use std::collections::HashMap;
+use regex::Regex;
+
+static DAY: u8 = 2;
+
+fn main() {
+    let input = advent::read_lines(DAY);
+    println!("{DAY}a: {}", sum_possible(&input));
+    println!("{DAY}b: {}", 0);
+}
+
+struct Game {
+    id: usize,
+    infos: Vec<HashMap<String, usize>>,
+}
+
+impl Game {
+    fn new(input: &str) -> Game {
+        let re = Regex::new("^Game ([0-9]+): (.*)").unwrap();
+        let caps = re.captures(input).unwrap();
+
+        let id = caps[1].parse().unwrap();
+        let mut infos = Vec::new();
+        for info in caps[2].split("; ") {
+            let mut color_amount = HashMap::new();
+            for color_info in info.split(", ") {
+                let (amount, color) = color_info.split_once(' ').unwrap();
+                let amount = amount.parse().unwrap();
+                color_amount.insert(color.to_string(), amount);
+            }
+            infos.push(color_amount);
+        }
+        Game { id, infos }
+    }
+
+    fn is_possible(&self, bagged: &HashMap<String, usize>) -> bool {
+        for info in &self.infos {
+            for (color, amount) in info {
+                if bagged[color] < *amount {
+                    return false
+                }
+            }
+        }
+        true
+    }
+}
+
+fn sum_possible(input: &[String]) -> usize {
+    let games = input.iter()
+                     .map(|x| Game::new(x))
+                     .collect::<Vec<Game>>();
+    let bag_content = HashMap::from([
+        ("red".to_string(), 12),
+        ("green".to_string(), 13),
+        ("blue".to_string(), 14),
+    ]);
+    games.iter()
+         .filter(|x| x.is_possible(&bag_content))
+         .map(|x| x.id)
+         .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = [
+            "Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green",
+            "Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue",
+            "Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red",
+            "Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red",
+            "Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green",
+         ].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
+        assert_eq!(sum_possible(&input), 8);
+    }
+}