Day 2

2023/rust/Cargo.lock

@@ -5,3 +5,28 @@ version = 3
 [[package]]
 name = "aoc2023"
 version = "1.0.0"
+dependencies = [
+ "nom",
+]
+
+[[package]]
+name = "memchr"
+version = "2.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"
+
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]

2023/rust/Cargo.toml

@@ -103,3 +103,4 @@ name = "day25"
 path = "src/day25.rs"
 
 [dependencies]
+nom = "7.1.3"

2023/rust/src/day2.rs

@@ -0,0 +1,140 @@
+use crate::prelude::*;
+
+extern crate nom;
+
+mod prelude;
+
+use nom::{
+    branch::alt,
+    bytes::complete::{tag, take_while_m_n},
+    combinator::{map_res, value},
+    multi::separated_list0,
+    IResult,
+};
+
+fn main() {
+    Day2::show(day_input(2), day_input(2))
+}
+
+type Solution = usize;
+
+#[derive(Debug, PartialEq, Clone)]
+enum Reveal {
+    Red(usize),
+    Green(usize),
+    Blue(usize),
+}
+
+#[derive(Debug, PartialEq)]
+struct RevealGroup {
+    red: Option<usize>,
+    green: Option<usize>,
+    blue: Option<usize>,
+}
+
+impl From<Vec<Reveal>> for RevealGroup {
+    fn from(value: Vec<Reveal>) -> Self {
+        // TODO: this obviously won't work if the vector contains multiple reveals of the same kind
+        // there's probably a simpler way to parse it out
+        let mut result = Self {
+            red: None,
+            blue: None,
+            green: None,
+        };
+        for v in value {
+            match v {
+                Reveal::Red(v) => result.red = Some(v),
+                Reveal::Green(v) => result.green = Some(v),
+                Reveal::Blue(v) => result.blue = Some(v),
+            }
+        }
+        result
+    }
+}
+
+#[derive(Debug, PartialEq)]
+struct Game {
+    id: usize,
+    reveal_groups: Vec<RevealGroup>,
+}
+
+fn int(input: &str) -> IResult<&str, usize> {
+    map_res(take_while_m_n(1, 16, |c: char| c.is_numeric()), |s| {
+        usize::from_str_radix(s, 10)
+    })(input)
+}
+
+fn reveal(input: &str) -> IResult<&str, Reveal> {
+    let (input, num) = int(input)?;
+    alt((
+        value(Reveal::Red(num), tag(" red")),
+        value(Reveal::Green(num), tag(" green")),
+        value(Reveal::Blue(num), tag(" blue")),
+    ))(input)
+}
+
+fn reveal_group(input: &str) -> IResult<&str, RevealGroup> {
+    let (input, reveals) = separated_list0(tag(", "), reveal)(input)?;
+    Ok((input, RevealGroup::from(reveals)))
+}
+
+fn game(input: &str) -> IResult<&str, Game> {
+    println!("that belle");
+    let (input, id) = int(tag("Game ")(input)?.0)?;
+    let (input, reveal_groups) = separated_list0(tag("; "), reveal_group)(tag(": ")(input)?.0)?;
+
+    println!("{id} {:?}", reveal_groups);
+    Ok((input, Game { id, reveal_groups }))
+}
+
+struct Day2 {}
+impl Day2 {}
+
+impl AoCSolution for Day2 {
+    type Input = String;
+    type Solution = Solution;
+
+    fn part1(input: Self::Input) -> Self::Solution {
+        const MAX_RED: Solution = 12;
+        const MAX_GREEN: Solution = 13;
+        const MAX_BLUE: Solution = 14;
+
+        let valid_reveal_group = |rg: &RevealGroup| {
+            rg.red.unwrap_or(0) <= MAX_RED
+                && rg.green.unwrap_or(0) <= MAX_GREEN
+                && rg.blue.unwrap_or(0) <= MAX_BLUE
+        };
+
+        input
+            .lines()
+            .map(|s| game(s).unwrap().1)
+            .filter(|g| g.reveal_groups.iter().all(valid_reveal_group))
+            .map(|g| g.id)
+            .sum()
+    }
+
+    fn part2(input: Self::Input) -> Self::Solution {
+        return 0;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        assert_eq!(
+            Day2::part1(
+                r#"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"#
+                    .into()
+            ),
+            8
+        );
+        assert_eq!(Day2::part2(r#""#.into()), 0);
+    }
+}