2024 day 1

Author: ictrobot

Cargo.lock

@@ -13,12 +13,13 @@ utils = { path = "../utils" }
 year2015 = { path = "../year2015", optional = true }
 year2016 = { path = "../year2016", optional = true }
 year2017 = { path = "../year2017", optional = true }
+year2024 = { path = "../year2024", optional = true }
 
 [features]
 default = ["all-years", "unsafe"]
 # xtask update features
-all-years = ["year2015", "year2016", "year2017"]
-unsafe = ["year2015?/unsafe", "year2016?/unsafe", "year2017?/unsafe", "utils/unsafe"]
+all-years = ["year2015", "year2016", "year2017", "year2024"]
+unsafe = ["year2015?/unsafe", "year2016?/unsafe", "year2017?/unsafe", "year2024?/unsafe", "utils/unsafe"]
 
 [lints]
 workspace = true

crates/aoc/Cargo.toml

@@ -23,12 +23,18 @@ pub mod year2016 {
 pub mod year2017 {
     pub use ::utils::puzzles_noop as puzzles;
 }
+#[cfg(not(feature = "year2024"))]
+pub mod year2024 {
+    pub use ::utils::puzzles_noop as puzzles;
+}
 #[cfg(feature = "year2015")]
 pub use ::year2015;
 #[cfg(feature = "year2016")]
 pub use ::year2016;
 #[cfg(feature = "year2017")]
 pub use ::year2017;
+#[cfg(feature = "year2024")]
+pub use ::year2024;
 
 /// Macro which invokes a callback macro with a list of all implemented puzzle solutions.
 ///
@@ -98,6 +104,7 @@ macro_rules! all_puzzles {
                 $crate::year2015::puzzles,
                 $crate::year2016::puzzles,
                 $crate::year2017::puzzles,
+                $crate::year2024::puzzles,
 
                 $callback
             ]

crates/aoc/src/years.rs

@@ -0,0 +1,14 @@
+[package]
+name = "year2024"
+authors = { workspace = true }
+edition = { workspace = true }
+license = { workspace = true }
+publish = { workspace = true }
+repository = { workspace = true }
+rust-version = { workspace = true }
+
+[dependencies]
+utils = { path = "../utils" }
+
+[features]
+unsafe = ["utils/unsafe"]

crates/year2024/Cargo.toml

@@ -0,0 +1 @@
+Solutions for [Advent of Code 2024](https://adventofcode.com/2024)

crates/year2024/README.md

@@ -0,0 +1,55 @@
+use utils::prelude::*;
+
+/// Comparing two lists of numbers.
+#[derive(Clone, Debug)]
+pub struct Day01 {
+    left: Vec<u32>,
+    right: Vec<u32>,
+}
+
+impl Day01 {
+    pub fn new(input: &str, _: InputType) -> Result<Self, InputError> {
+        let pairs = parser::u32()
+            .then(parser::u32().with_prefix("   "))
+            .parse_lines(input)?;
+
+        let mut left = pairs.iter().map(|x| x.0).collect::<Vec<_>>();
+        left.sort_unstable();
+
+        let mut right = pairs.into_iter().map(|x| x.1).collect::<Vec<_>>();
+        right.sort_unstable();
+
+        Ok(Self { left, right })
+    }
+
+    #[must_use]
+    pub fn part1(&self) -> u32 {
+        self.left
+            .iter()
+            .zip(&self.right)
+            .map(|(&l, &r)| l.abs_diff(r))
+            .sum()
+    }
+
+    #[must_use]
+    pub fn part2(&self) -> u32 {
+        let mut score = 0;
+        let mut i = 0;
+        for &l in &self.left {
+            while i < self.right.len() && self.right[i] < l {
+                i += 1;
+            }
+
+            let mut j = i;
+            while j < self.right.len() && self.right[j] == l {
+                score += l;
+                j += 1;
+            }
+        }
+        score
+    }
+}
+
+examples!(Day01 -> (u32, u32) [
+    {input: "3   4\n4   3\n2   5\n1   3\n3   9\n3   3", part1: 11, part2: 31},
+]);

crates/year2024/src/day01.rs

@@ -0,0 +1,6 @@
+#![doc = include_str!("../README.md")]
+#![cfg_attr(not(feature = "unsafe"), forbid(unsafe_code))]
+
+utils::year!(2024 => year2024, ${
+    1 => day01::Day01,
+});