1 files changed, 53 insertions, 0 deletions
diff --git a/aoc02/src/main.rs b/aoc02/src/main.rs
new file mode 100644
index 0000000..b8b5eae
--- /dev/null
+++ b/aoc02/src/main.rs
@@ -0,0 +1,53 @@
+use std::{collections::BTreeMap, env::args, io::stdin};
+
+fn rounds_are_possible(rounds: &str) -> bool {
+    !rounds
+        .split(&[';', ','])
+        .map(|round| round.trim().split_once(' ').expect("bad input whitespace"))
+        .map(|(score, color)| (score.parse::<u32>().expect("input score not digit"), color))
+        .map(|(score, color)| {
+            color == "red" && score > 12
+                || color == "blue" && score > 14
+                || color == "green" && score > 13
+        })
+        .any(|p| p)
+}
+
+fn rounds_power(rounds: &str) -> u32 {
+    let mut maximums = BTreeMap::new();
+
+    for (score, color) in rounds
+        .split(&[';', ','])
+        .map(|round| round.trim().split_once(' ').expect("bad input whitespace"))
+        .map(|(score, color)| (score.parse::<u32>().expect("input score not digit"), color))
+    {
+        if &score > maximums.get(color).unwrap_or(&0) {
+            maximums.insert(color, score);
+        }
+    }
+
+    maximums.values().product()
+}
+
+fn main() {
+    let b_mode = args().any(|b| b == "-b");
+    let mut lines = stdin().lines();
+    let mut possibilities = Vec::new();
+
+    while let Some(Ok(line)) = lines.next() {
+        let line = line
+            .strip_prefix("Game ")
+            .expect("input missing game prefix");
+        let (id, rounds) = line
+            .split_once(": ")
+            .expect("input missing colon separator");
+
+        if !b_mode && rounds_are_possible(rounds) {
+            possibilities.push(id.parse::<u32>().expect("input id not integers"));
+        } else if b_mode {
+            possibilities.push(rounds_power(rounds));
+        }
+    }
+
+    println!("{}", possibilities.iter().sum::<u32>());
+}