Day 5: Print Queue

README.md

@@ -9,4 +9,4 @@ Development occurs in language-specific directories:
 |[Day2.hs](hs/src/Day2.hs)|[Day2.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day2.kt)|[day2.py](py/aoc2024/day2.py)|[day2.rs](rs/src/day2.rs)|
 |[Day3.hs](hs/src/Day3.hs)|[Day3.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day3.kt)|[day3.py](py/aoc2024/day3.py)|[day3.rs](rs/src/day3.rs)|
 |[Day4.hs](hs/src/Day4.hs)|[Day4.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day4.kt)|[day4.py](py/aoc2024/day4.py)|[day4.rs](rs/src/day4.rs)|
-|[Day5.hs](hs/src/Day5.hs)|[Day5.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day5.kt)|[day5.py](py/aoc2024/day5.py)||
+|[Day5.hs](hs/src/Day5.hs)|[Day5.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day5.kt)|[day5.py](py/aoc2024/day5.py)|[day5.rs](rs/src/day5.rs)|

rs/Cargo.toml

@@ -17,8 +17,10 @@ name = "aoc2024"
 path = "src/main.rs"
 
 [dependencies]
-array-util = "1.0.2"
+anyhow = "1.0"
+array-util = "1"
 itertools = "0.13"
+thiserror = "2"
 
 [dev-dependencies]
 criterion = "0.5.1"

rs/benches/criterion.rs

@@ -1,4 +1,4 @@
-use aoc2024::{day1, day2, day3, day4};
+use aoc2024::{day1, day2, day3, day4, day5};
 use criterion::{black_box, Criterion};
 use std::env;
 use std::fs;
@@ -38,6 +38,12 @@ fn aoc2024_bench(c: &mut Criterion) -> io::Result<()> {
     g.bench_function("part 2", |b| b.iter(|| day4::part2(black_box(&data))));
     g.finish();
 
+    let data = get_day_input(5)?;
+    let mut g = c.benchmark_group("day 5");
+    g.bench_function("part 1", |b| b.iter(|| day5::part1(black_box(&data))));
+    g.bench_function("part 2", |b| b.iter(|| day5::part2(black_box(&data))));
+    g.finish();
+
     Ok(())
 }
 

rs/src/day5.rs

@@ -0,0 +1,130 @@
+use std::collections::BTreeSet;
+use std::mem::swap;
+use std::num::ParseIntError;
+
+#[derive(Debug, Eq, PartialEq, thiserror::Error)]
+pub enum Error {
+    #[error("Format")]
+    Format,
+    #[error("Parse({0})")]
+    Parse(ParseIntError),
+}
+
+impl From<ParseIntError> for Error {
+    fn from(value: ParseIntError) -> Self {
+        Self::Parse(value)
+    }
+}
+
+type ParsedInput = (BTreeSet<(u32, u32)>, Vec<Vec<u32>>);
+
+fn parse(data: &str) -> Result<ParsedInput, Error> {
+    let (deps, updates) = data.split_once("\n\n").ok_or(Error::Format)?;
+    let deps = deps
+        .lines()
+        .map(|line| {
+            let (x, y) = line.split_once('|').ok_or(Error::Format)?;
+            Ok((x.parse()?, y.parse()?))
+        })
+        .collect::<Result<_, Error>>()?;
+    let updates = updates
+        .lines()
+        .map(|line| line.split(',').map(|page| page.parse::<u32>()).collect())
+        .collect::<Result<Vec<_>, _>>()?;
+    Ok((deps, updates))
+}
+
+pub fn part1(data: &str) -> Result<u32, Error> {
+    let (deps, updates) = parse(data)?;
+    Ok(updates
+        .into_iter()
+        .filter_map(|pages| {
+            if pages
+                .iter()
+                .enumerate()
+                .all(|(i, x)| pages[i + 1..].iter().all(|y| !deps.contains(&(*y, *x))))
+            {
+                pages.get(pages.len() / 2).copied()
+            } else {
+                None
+            }
+        })
+        .sum())
+}
+
+pub fn part2(data: &str) -> Result<u32, Error> {
+    let (deps, updates) = parse(data)?;
+    Ok(updates
+        .into_iter()
+        .filter_map(|mut pages| {
+            let mut deranged = false;
+            for i in 0..pages.len() {
+                let pages = &mut pages[i..];
+                'scan: loop {
+                    let (x, pages) = pages.split_first_mut().unwrap();
+                    for y in pages.iter_mut() {
+                        if deps.contains(&(*y, *x)) {
+                            deranged = true;
+                            swap(x, y);
+                            continue 'scan;
+                        }
+                    }
+                    break;
+                }
+            }
+            if deranged {
+                pages.get(pages.len() / 2).copied()
+            } else {
+                None
+            }
+        })
+        .sum())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use indoc::indoc;
+    use pretty_assertions::assert_eq;
+
+    static EXAMPLE: &str = indoc! {"
+        47|53
+        97|13
+        97|61
+        97|47
+        75|29
+        61|13
+        75|53
+        29|13
+        97|29
+        53|29
+        61|53
+        97|53
+        61|29
+        47|13
+        75|47
+        97|75
+        47|61
+        75|61
+        47|29
+        75|13
+        53|13
+
+        75,47,61,53,29
+        97,61,53,29,13
+        75,29,13
+        75,97,47,61,53
+        61,13,29
+        97,13,75,29,47
+    "};
+
+    #[test]
+    fn part1_examples() {
+        assert_eq!(Ok(143), part1(EXAMPLE));
+    }
+
+    #[test]
+    fn part2_examples() {
+        assert_eq!(Ok(123), part2(EXAMPLE));
+    }
+}

rs/src/lib.rs

@@ -2,3 +2,4 @@ pub mod day1;
 pub mod day2;
 pub mod day3;
 pub mod day4;
+pub mod day5;

rs/src/main.rs

@@ -1,4 +1,4 @@
-use aoc2024::{day1, day2, day3, day4};
+use aoc2024::{day1, day2, day3, day4, day5};
 use std::collections::HashSet;
 use std::env;
 use std::fs;
@@ -13,7 +13,7 @@ fn get_day_input(day: u8) -> io::Result<String> {
     fs::read_to_string(Path::new(&datadir).join(format!("day{}.txt", day)))
 }
 
-fn main() -> io::Result<()> {
+fn main() -> anyhow::Result<()> {
     let args = env::args().skip(1).collect::<HashSet<_>>();
 
     if args.is_empty() || args.contains("1") {
@@ -48,5 +48,13 @@ fn main() -> io::Result<()> {
         println!();
     }
 
+    if args.is_empty() || args.contains("5") {
+        println!("Day 5");
+        let data = get_day_input(5)?;
+        println!("{:?}", day5::part1(&data)?);
+        println!("{:?}", day5::part2(&data)?);
+        println!();
+    }
+
     Ok(())
 }