diff --git a/day2/.gitignore b/day2/.gitignore
new file mode 100644
index 0000000..eb5a316
--- /dev/null
+++ b/day2/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/day2/Cargo.lock b/day2/Cargo.lock
new file mode 100644
index 0000000..14884f5
--- /dev/null
+++ b/day2/Cargo.lock
@@ -0,0 +1,54 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "aho-corasick"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2969dcb958b36655471fc61f7e416fa76033bdd4bfed0678d8fee1e2d07a1f0"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "day2"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "memchr"
+version = "2.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"
+
+[[package]]
+name = "regex"
+version = "1.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "380b951a9c5e80ddfd6136919eef32310721aa4aacd4889a8d39124b026ab343"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f804c7828047e88b2d32e2d7fe5a105da8ee3264f01902f796c8e067dc2483f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
diff --git a/day2/Cargo.toml b/day2/Cargo.toml
new file mode 100644
index 0000000..59b0ab3
--- /dev/null
+++ b/day2/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "day2"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+regex = "1.10.2"
diff --git a/day2/input b/day2/input
new file mode 100644
index 0000000..88703fa
--- /dev/null
+++ b/day2/input
@@ -0,0 +1,100 @@
+Game 1: 2 red, 2 green; 1 red, 1 green, 2 blue; 3 blue, 3 red, 3 green; 1 blue, 3 green, 7 red; 5 red, 3 green, 1 blue
+Game 2: 5 green, 4 red, 7 blue; 7 red, 4 green, 4 blue; 8 green, 11 blue, 4 red; 2 red, 18 blue, 3 green; 7 red, 15 blue
+Game 3: 2 green, 4 blue; 2 red, 2 green; 6 red, 1 green; 2 red, 1 green; 2 green; 5 blue, 5 red
+Game 4: 10 red, 7 green, 10 blue; 8 red, 2 green; 9 green, 6 red, 5 blue; 8 green, 2 blue, 4 red; 5 green, 9 blue; 10 red, 1 green, 9 blue
+Game 5: 10 blue, 7 green, 2 red; 2 blue, 4 red; 2 green, 9 blue, 8 red
+Game 6: 3 green, 8 red; 1 blue, 11 red, 2 green; 2 green, 15 red, 8 blue; 13 red, 6 blue, 3 green
+Game 7: 4 green, 10 red, 7 blue; 6 red, 9 blue, 9 green; 2 red, 1 blue, 6 green
+Game 8: 1 red, 3 blue, 2 green; 7 green, 2 blue; 10 green, 1 red, 2 blue; 1 red
+Game 9: 4 red, 3 green, 11 blue; 6 red, 4 green; 15 red, 7 blue, 7 green
+Game 10: 7 red, 1 blue, 5 green; 11 red, 7 green, 1 blue; 2 green, 4 blue, 13 red
+Game 11: 2 blue, 13 red, 12 green; 6 green, 5 red, 4 blue; 5 red, 11 green
+Game 12: 7 blue, 3 red, 11 green; 5 red, 1 blue, 8 green; 9 green, 7 blue, 8 red
+Game 13: 1 blue, 12 red; 9 red, 1 green, 1 blue; 8 red; 1 green, 4 red; 2 red
+Game 14: 6 blue, 5 green, 1 red; 12 blue, 4 red, 9 green; 7 green, 6 red; 8 blue, 10 green, 4 red; 8 green, 7 red
+Game 15: 15 blue, 10 red, 3 green; 9 green, 6 red, 11 blue; 3 green, 8 red, 5 blue; 12 green, 6 red, 16 blue; 11 red, 9 green, 15 blue
+Game 16: 12 green, 2 red, 7 blue; 9 red, 6 blue, 9 green; 7 green, 10 blue; 9 blue, 3 red, 9 green; 5 blue, 1 red
+Game 17: 4 green, 3 red, 11 blue; 8 green, 16 blue; 10 green, 12 blue, 2 red; 8 green, 2 red, 15 blue
+Game 18: 6 red, 8 green; 16 blue; 4 blue, 6 red; 16 blue, 10 green, 3 red; 12 blue, 15 green; 9 blue, 1 green, 4 red
+Game 19: 9 green, 9 red; 4 green, 13 red, 2 blue; 2 blue, 4 green, 3 red; 5 green, 3 blue, 3 red
+Game 20: 1 green, 6 red, 12 blue; 3 green, 8 red, 11 blue; 7 green, 5 red, 2 blue; 5 green, 14 blue, 5 red
+Game 21: 5 green, 1 blue, 13 red; 3 green, 13 red, 2 blue; 8 green, 12 red, 3 blue; 3 blue, 6 green, 9 red; 1 blue, 4 green, 13 red
+Game 22: 8 green, 14 red, 15 blue; 10 blue, 8 red, 14 green; 15 green, 15 blue, 6 red; 14 green, 10 blue, 7 red
+Game 23: 18 red, 9 green; 3 green, 1 blue, 17 red; 10 red, 16 green
+Game 24: 1 red, 2 blue, 4 green; 2 red, 5 blue, 3 green; 5 green, 5 blue; 8 blue, 1 red, 3 green; 2 green, 2 red, 6 blue; 2 green, 4 blue
+Game 25: 5 blue, 4 red, 1 green; 4 blue, 8 red, 1 green; 6 red, 5 blue; 8 red; 9 red, 3 blue; 1 green, 3 blue, 5 red
+Game 26: 20 blue, 4 red, 15 green; 10 red, 2 green, 12 blue; 7 blue, 15 green, 9 red; 1 red, 10 green, 5 blue; 14 green, 7 red, 15 blue
+Game 27: 17 red, 6 green; 6 green, 5 red, 3 blue; 4 green, 4 red, 5 blue; 3 green, 3 blue, 16 red; 4 blue, 5 green, 15 red
+Game 28: 5 blue, 6 green, 1 red; 13 blue; 1 red, 9 blue, 10 green
+Game 29: 1 red, 10 blue; 9 green, 6 blue, 3 red; 17 green, 1 red, 9 blue; 7 blue, 1 red; 1 red, 15 blue, 9 green; 7 green, 1 red, 4 blue
+Game 30: 3 red, 11 blue, 2 green; 11 green, 8 blue, 8 red; 1 red, 3 green; 19 green, 11 blue
+Game 31: 19 green, 6 red; 4 green, 10 red; 12 green, 1 blue
+Game 32: 4 green, 3 blue, 10 red; 4 red, 6 blue, 3 green; 10 red, 5 blue
+Game 33: 2 blue, 5 green, 5 red; 4 blue, 2 green, 4 red; 13 red, 2 green; 7 blue, 4 green, 2 red; 19 blue, 5 green, 11 red; 4 green, 18 blue, 1 red
+Game 34: 6 blue, 9 red, 7 green; 7 green, 6 red, 12 blue; 3 red, 6 green, 16 blue; 3 green, 15 blue, 13 red; 2 green, 16 blue, 3 red
+Game 35: 4 green; 3 green, 4 red, 1 blue; 6 red, 12 green, 2 blue
+Game 36: 1 blue, 8 red, 3 green; 10 red, 5 green; 1 green, 8 red; 4 green, 1 blue, 11 red
+Game 37: 2 red, 4 blue, 5 green; 2 green, 1 blue, 3 red; 8 green, 3 red, 4 blue; 1 blue, 8 green, 2 red
+Game 38: 11 green, 4 blue; 2 blue, 11 green, 1 red; 12 green, 7 blue, 1 red; 7 blue, 10 green, 1 red; 13 green, 2 red; 1 red, 7 blue, 2 green
+Game 39: 7 green, 1 red, 15 blue; 8 red, 7 blue; 15 red, 5 green, 6 blue
+Game 40: 2 green, 12 blue, 15 red; 2 green, 6 red; 5 green, 9 red; 9 blue, 12 red; 4 green, 12 red, 12 blue; 12 red, 8 blue, 2 green
+Game 41: 9 blue, 6 red, 3 green; 6 red, 2 green, 9 blue; 1 blue, 11 red
+Game 42: 4 red, 3 blue, 13 green; 5 blue, 11 red, 15 green; 3 red, 12 green; 2 red, 6 blue, 3 green
+Game 43: 2 green, 7 red; 11 red, 18 green, 1 blue; 13 red, 12 green, 1 blue; 15 red; 5 red, 19 green; 15 green, 5 red
+Game 44: 2 red, 5 green, 7 blue; 5 green, 8 blue; 8 red, 8 green; 1 green, 1 red, 6 blue; 1 blue, 1 red
+Game 45: 3 red, 3 green, 7 blue; 12 red, 17 blue; 7 green, 8 red, 14 blue; 9 green, 10 red, 13 blue; 15 green, 16 blue, 4 red
+Game 46: 2 blue, 5 green; 4 red, 7 green; 15 red, 7 green
+Game 47: 5 red, 9 green, 4 blue; 1 red, 9 green, 11 blue; 8 green, 1 red; 4 red, 4 blue, 3 green; 10 blue, 14 green
+Game 48: 1 red, 14 blue, 11 green; 3 blue, 8 green; 5 green, 5 blue; 5 blue, 1 red, 8 green; 10 green, 2 red, 6 blue
+Game 49: 11 blue, 5 red, 3 green; 7 blue, 12 red, 4 green; 9 green, 6 red; 4 green, 3 blue, 10 red
+Game 50: 3 red, 8 blue, 13 green; 13 blue, 13 green; 3 green, 10 blue, 1 red; 12 green, 15 blue; 12 blue, 3 red, 8 green; 5 blue, 5 red, 4 green
+Game 51: 3 green, 1 blue; 1 red; 1 green, 7 blue
+Game 52: 3 red, 4 blue; 4 blue, 1 green, 2 red; 1 green, 3 red; 5 red, 1 green; 1 blue, 1 red, 1 green
+Game 53: 5 red, 17 green, 4 blue; 15 red, 14 blue, 1 green; 9 blue, 5 green; 3 blue, 5 red, 9 green; 1 green, 15 blue, 10 red; 16 green, 10 blue
+Game 54: 4 blue, 7 red, 1 green; 7 green, 8 red, 6 blue; 14 green, 1 blue, 5 red
+Game 55: 4 blue, 4 green, 1 red; 1 green; 3 red
+Game 56: 3 green, 1 red, 7 blue; 1 blue, 2 red, 3 green; 2 green, 9 red; 14 red, 8 blue, 1 green; 5 red, 13 blue; 6 red, 3 blue
+Game 57: 15 green, 5 red, 5 blue; 13 green, 13 blue, 12 red; 18 green, 5 blue, 8 red; 7 green, 7 blue, 13 red
+Game 58: 4 red, 2 blue, 6 green; 4 red, 3 green, 14 blue; 9 green, 3 red; 3 red, 5 blue, 11 green
+Game 59: 2 red, 6 green, 1 blue; 5 blue, 1 green, 4 red; 2 red, 7 green, 6 blue; 3 green, 6 blue; 1 blue, 6 green
+Game 60: 4 red, 9 green, 3 blue; 2 blue, 8 green, 6 red; 2 red, 8 green, 3 blue; 8 green, 2 red, 2 blue
+Game 61: 12 red, 4 blue, 3 green; 1 blue, 2 green; 2 red, 2 green, 3 blue
+Game 62: 4 red, 6 green, 14 blue; 12 green, 2 red, 4 blue; 5 blue, 5 red, 7 green
+Game 63: 1 green, 5 red; 5 red, 1 blue, 1 green; 1 blue
+Game 64: 6 red, 9 green, 4 blue; 8 red, 13 green; 3 blue, 8 red, 11 green; 5 red, 1 blue, 2 green; 3 blue, 7 red, 1 green
+Game 65: 15 green, 10 red, 1 blue; 1 blue, 2 red, 4 green; 10 blue, 4 green
+Game 66: 13 blue, 6 red, 2 green; 13 green; 10 blue, 8 green; 7 red, 10 blue, 11 green; 10 green, 1 red, 8 blue
+Game 67: 5 blue, 4 green, 1 red; 2 green, 4 blue, 1 red; 7 green, 2 blue, 1 red; 1 blue, 1 green
+Game 68: 2 green, 12 blue, 3 red; 5 red, 14 blue, 2 green; 6 red, 14 blue; 10 blue, 6 red, 2 green
+Game 69: 7 blue, 1 red, 12 green; 10 blue, 11 green, 6 red; 4 red, 10 green, 7 blue
+Game 70: 4 blue; 6 red, 2 green, 11 blue; 4 green, 3 blue, 2 red; 14 blue, 2 red, 4 green
+Game 71: 5 red, 17 blue; 9 blue, 11 red, 1 green; 19 blue, 6 red; 4 red, 2 blue
+Game 72: 2 green, 5 red, 1 blue; 4 green, 4 red; 4 green, 2 red; 2 blue, 2 green; 1 blue, 1 green, 5 red
+Game 73: 4 red, 3 blue, 1 green; 10 red, 2 blue, 3 green; 14 red, 1 green, 2 blue; 1 blue; 3 green, 9 red, 6 blue; 11 red, 7 blue, 2 green
+Game 74: 1 red, 5 blue, 10 green; 2 red, 9 blue, 9 green; 8 green, 2 red, 4 blue; 10 blue, 9 green; 12 green, 3 red, 5 blue
+Game 75: 3 red, 13 blue, 6 green; 3 green, 1 red; 9 green, 1 blue, 5 red; 5 green, 13 red, 4 blue; 13 green, 2 blue, 10 red; 9 green, 3 red, 10 blue
+Game 76: 14 green, 2 red, 16 blue; 2 blue, 1 red, 7 green; 14 green, 9 blue, 8 red
+Game 77: 1 green, 1 blue; 1 green; 3 red, 3 blue, 1 green; 3 green, 3 red; 1 red, 2 blue
+Game 78: 4 red, 13 green; 17 green, 1 blue, 2 red; 8 red, 14 green
+Game 79: 4 green, 10 red, 6 blue; 5 blue, 3 red, 7 green; 6 blue, 2 red, 4 green; 2 blue, 8 red
+Game 80: 19 green, 5 red; 5 green, 9 blue; 3 red, 18 blue, 10 green; 2 red, 15 green, 7 blue; 4 red, 14 green, 15 blue
+Game 81: 10 red, 2 blue, 1 green; 18 red, 3 blue; 6 red, 12 blue; 1 green, 3 red, 3 blue
+Game 82: 8 green, 1 blue; 2 blue, 4 red; 7 green, 1 red, 4 blue; 2 green, 3 red, 2 blue; 3 red; 4 red, 8 green, 1 blue
+Game 83: 3 green, 1 blue; 1 red, 2 blue, 14 green; 8 red, 17 green
+Game 84: 7 green, 4 blue, 4 red; 11 green, 17 red, 11 blue; 9 green, 5 blue, 14 red; 9 green, 10 blue, 5 red
+Game 85: 1 red, 1 green; 1 blue, 8 red, 1 green; 8 green, 1 red; 8 green, 2 red, 1 blue
+Game 86: 1 red, 5 blue, 1 green; 1 green, 7 red; 8 red; 3 blue, 2 red
+Game 87: 7 red, 8 blue, 1 green; 8 red, 6 green; 6 red, 8 green, 10 blue
+Game 88: 5 red, 4 green, 5 blue; 1 blue, 2 green; 6 green, 10 blue, 4 red; 1 red, 8 green, 1 blue
+Game 89: 3 green, 7 blue, 11 red; 1 blue, 5 green, 18 red; 1 blue, 3 green, 13 red; 7 blue, 9 green, 3 red; 1 green, 8 blue, 19 red; 4 blue, 15 red, 1 green
+Game 90: 3 blue, 3 red, 4 green; 14 red, 6 green, 4 blue; 1 blue, 9 red; 6 red, 1 green; 5 green, 8 red, 2 blue; 3 blue, 4 red, 3 green
+Game 91: 1 red, 1 blue, 16 green; 8 red, 5 green; 1 blue, 2 red, 10 green; 3 red, 15 green, 1 blue
+Game 92: 10 green, 12 blue; 6 red, 6 blue; 5 red, 12 blue; 6 red, 9 green, 2 blue; 10 blue, 3 red, 1 green; 1 red, 19 blue, 11 green
+Game 93: 4 green; 5 green, 2 blue, 3 red; 1 blue, 3 red, 6 green; 2 blue, 2 red, 7 green
+Game 94: 4 blue, 2 red; 6 green, 6 blue, 4 red; 8 green, 1 blue, 3 red
+Game 95: 6 green, 4 blue, 15 red; 13 red, 7 blue, 3 green; 14 red, 5 blue, 6 green; 5 blue, 7 red, 2 green
+Game 96: 1 red, 1 blue, 11 green; 6 blue, 2 red, 14 green; 3 green, 2 red; 9 blue, 10 green
+Game 97: 10 green; 2 red, 4 green, 1 blue; 2 green, 1 red; 2 red, 1 blue, 10 green; 1 green
+Game 98: 1 green, 5 blue; 2 green, 7 blue, 4 red; 2 red, 1 green, 9 blue; 4 blue, 4 red
+Game 99: 3 green, 1 red, 3 blue; 12 green, 12 blue, 4 red; 12 blue, 2 red, 10 green; 4 blue, 2 red, 4 green
+Game 100: 1 red, 5 blue, 2 green; 3 red, 1 blue; 1 green, 1 blue, 1 red
diff --git a/day2/src/main.rs b/day2/src/main.rs
new file mode 100644
index 0000000..ebd9936
--- /dev/null
+++ b/day2/src/main.rs
@@ -0,0 +1,215 @@
+#![feature(lazy_cell)]
+use regex::Regex;
+use std::fs::File;
+use std::{
+    io::{BufRead, BufReader},
+    sync::LazyLock,
+};
+
+fn main() {
+    let input = parse();
+    let part1_result = part1(&input);
+    let part2_result = part2(&input);
+    println!("part 1: {part1_result}");
+    println!("part 2: {part2_result}");
+}
+
+fn parse() -> Vec<Game> {
+    BufReader::new(File::open("input").expect("input file"))
+        .lines()
+        .map(|line| Game::parse(&line.expect("line")))
+        .collect()
+}
+
+fn part1(input: &[Game]) -> u32 {
+    input
+        .iter()
+        .filter_map(|game| {
+            for round in &game.rounds {
+                if round.red > 12 || round.green > 13 || round.blue > 14 {
+                    return None;
+                }
+            }
+            Some(game.number)
+        })
+        .sum()
+}
+
+fn part2(input: &[Game]) -> u32 {
+    input
+        .iter()
+        .map(|game| {
+            let mut min = Bag::default();
+            for round in &game.rounds {
+                if round.red > min.red {
+                    min.red = round.red;
+                }
+                if round.green > min.green {
+                    min.green = round.green;
+                }
+                if round.blue > min.blue {
+                    min.blue = round.blue;
+                }
+            }
+            min.power()
+        })
+        .sum()
+}
+
+static PATTERN: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"(\d+) (red|green|blue)").unwrap());
+
+#[derive(Default, Debug, Copy, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+struct Bag {
+    red: u8,
+    green: u8,
+    blue: u8,
+}
+
+impl std::ops::Add for Bag {
+    type Output = Bag;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Bag {
+            red: self.red + rhs.red,
+            green: self.green + rhs.green,
+            blue: self.blue + rhs.blue,
+        }
+    }
+}
+
+impl std::ops::AddAssign for Bag {
+    fn add_assign(&mut self, rhs: Self) {
+        self.red += rhs.red;
+        self.green += rhs.green;
+        self.blue += rhs.blue;
+    }
+}
+
+impl std::iter::Sum for Bag {
+    fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
+        let mut out = Default::default();
+        for value in iter {
+            out += value;
+        }
+        out
+    }
+}
+
+impl Bag {
+    fn parse(text: &str) -> Bag {
+        text.split(", ")
+            .map(|color| {
+                let caps = PATTERN
+                    .captures(color)
+                    .unwrap_or_else(|| panic!("unable to parse {color}"));
+                match &caps[2] {
+                    "red" => Bag::red(caps[1].parse().expect("valid color value")),
+                    "green" => Bag::green(caps[1].parse().expect("valid color value")),
+                    "blue" => Bag::blue(caps[1].parse().expect("valid color value")),
+                    _ => panic!("invalid color {color}"),
+                }
+            })
+            .sum()
+    }
+    fn red(val: u8) -> Self {
+        Self {
+            red: val,
+            ..Default::default()
+        }
+    }
+    fn green(val: u8) -> Self {
+        Self {
+            green: val,
+            ..Default::default()
+        }
+    }
+    fn blue(val: u8) -> Self {
+        Self {
+            blue: val,
+            ..Default::default()
+        }
+    }
+
+    // "The power of a set of cubes is equal to the numbers of red, green, and
+    // blue cubes multiplied together."
+    fn power(&self) -> u32 {
+        self.red as u32 * self.green as u32 * self.blue as u32
+    }
+}
+
+#[derive(Debug, Default, PartialEq, PartialOrd, Eq, Ord)]
+struct Game {
+    number: u32,
+    rounds: Vec<Bag>,
+}
+
+impl Game {
+    fn parse(line: &str) -> Self {
+        let colon_index = line.find(":").expect("colon");
+        let game_number = line[5..colon_index].parse().expect("game number");
+        // cuz "Game " is 5 letters ^
+        let rounds = line[colon_index + 1..]
+            .split("; ")
+            .map(Bag::parse)
+            .collect();
+        Self {
+            number: game_number,
+            rounds,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+
+    use crate::Bag;
+    use crate::Game;
+
+    use std::collections::HashMap;
+
+    // from https://stackoverflow.com/questions/27582739/how-do-i-create-a-hashmap-literal
+    macro_rules! collection {
+        // map-like
+        ($($k:expr => $v:expr),* $(,)?) => {{
+            core::convert::From::from([$(($k, $v),)*])
+        }};
+        // set-like
+        ($($v:expr),* $(,)?) => {{
+            core::convert::From::from([$($v,)*])
+        }};
+    }
+    #[test]
+    fn test_bag_parse() {
+        let examples: HashMap<_, _> = collection! {
+            Bag { blue: 3, red: 4, green: 0 } => "3 blue, 4 red",
+            Bag { red: 1, green: 2, blue: 6 } => "1 red, 2 green, 6 blue",
+            Bag::green(2) => "2 green",
+        };
+        for (example, plaintext) in examples.iter() {
+            assert_eq!(example, &Bag::parse(plaintext));
+        }
+    }
+
+    #[test]
+    fn test_game_parse() {
+        assert_eq!(
+            Game::parse("Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green"),
+            Game {
+                number: 1,
+                rounds: vec![
+                    Bag {
+                        blue: 3,
+                        red: 4,
+                        green: 0
+                    },
+                    Bag {
+                        red: 1,
+                        green: 2,
+                        blue: 6
+                    },
+                    Bag::green(2),
+                ]
+            }
+        )
+    }
+}