Cleanup

2023/rust/src/day2.rs

@@ -1,25 +1,19 @@
-use std::cmp::{max, min};
-
-use crate::prelude::*;
-
-extern crate nom;
-
 mod prelude;
-
+extern crate nom;
+use crate::prelude::*;
 use nom::{
     branch::alt,
-    bytes::complete::{tag, take_while_m_n},
+    bytes::complete::{tag, take_while},
     combinator::{map_res, value},
     multi::separated_list0,
     IResult,
 };
+use std::cmp::max;
 
 fn main() {
     Day2::show(day_input(2), day_input(2))
 }
 
-type Solution = usize;
-
 #[derive(Debug, PartialEq, Clone)]
 enum Reveal {
     Red(usize),
@@ -27,68 +21,15 @@ enum Reveal {
     Blue(usize),
 }
 
-#[derive(Debug, PartialEq)]
-struct RevealGroup {
-    red: Option<usize>,
-    green: Option<usize>,
-    blue: Option<usize>,
-}
-
-impl RevealGroup {
-    fn power(&self) -> usize {
-        println!("reveal group power for {:?}", self);
-        self.red.unwrap_or(0) * self.green.unwrap_or(0) * self.blue.unwrap_or(0)
-    }
-}
-
-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>,
-}
-
-impl Game {
-    fn made_possible(&self) -> RevealGroup {
-        let mut red = 0;
-        let mut green = 0;
-        let mut blue = 0;
-        for rg in &self.reveal_groups {
-            red = max(rg.red.unwrap_or(0), red);
-            green = max(rg.green.unwrap_or(0), green);
-            blue = max(rg.blue.unwrap_or(0), blue);
-        }
-        RevealGroup {
-            red: Some(red),
-            green: Some(green),
-            blue: Some(blue),
-        }
-    }
+    reveals: Vec<Reveal>,
 }
 
+// parser
 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)
+    map_res(take_while(char::is_numeric), str::parse)(input)
 }
 
 fn reveal(input: &str) -> IResult<&str, Reveal> {
@@ -100,40 +41,44 @@ fn reveal(input: &str) -> IResult<&str, Reveal> {
     ))(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> {
     let (input, id) = int(tag("Game ")(input)?.0)?;
-    let (input, reveal_groups) = separated_list0(tag("; "), reveal_group)(tag(": ")(input)?.0)?;
+    let (input, reveals) =
+        separated_list0(alt((tag(", "), tag("; "))), reveal)(tag(": ")(input)?.0)?;
+    Ok((input, Game { id, reveals }))
+}
 
-    Ok((input, Game { id, reveal_groups }))
+impl Game {
+    fn possible_power(&self) -> usize {
+        // TODO: probably the last place to cleanup nicely
+        let mut factors: [usize; 3] = [0, 0, 0];
+        for r in &self.reveals {
+            match r {
+                Reveal::Red(n) => factors[0] = max(*n, factors[0]),
+                Reveal::Green(n) => factors[1] = max(*n, factors[1]),
+                Reveal::Blue(n) => factors[2] = max(*n, factors[2]),
+            }
+        }
+        factors.iter().fold(1, |a, b| a * b)
+    }
 }
 
 struct Day2 {}
-impl Day2 {}
-
 impl AoCSolution for Day2 {
     type Input = String;
-    type Solution = Solution;
+    type Solution = usize;
 
     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
+        let valid = |r: &Reveal| match r {
+            Reveal::Red(n) => *n <= 12,
+            Reveal::Green(n) => *n <= 13,
+            Reveal::Blue(n) => *n <= 14,
         };
 
         input
             .lines()
             .map(|s| game(s).unwrap().1)
-            .filter(|g| g.reveal_groups.iter().all(valid_reveal_group))
+            .filter(|g| g.reveals.iter().all(valid))
             .map(|g| g.id)
             .sum()
     }
@@ -141,7 +86,7 @@ impl AoCSolution for Day2 {
     fn part2(input: Self::Input) -> Self::Solution {
         input
             .lines()
-            .map(|s| game(s).unwrap().1.made_possible().power())
+            .map(|s| game(s).unwrap().1.possible_power())
             .sum()
     }
 }

2023/rust/src/prelude.rs

@@ -4,8 +4,6 @@ pub use std::io::Read;
 use std::path::{Path, PathBuf};
 use std::{env, io};
 
-pub type Reader = Box<dyn Read>;
-
 #[derive(Debug)]
 enum InputFileError {
     VarError(env::VarError),