day 5 part 2

Cargo.lock

@@ -35,6 +35,7 @@ dependencies = [
  "bit-vec",
  "chumsky",
  "indexmap",
+ "itertools",
  "paste",
 ]
 
@@ -79,6 +80,12 @@ dependencies = [
  "stacker",
 ]
 
+[[package]]
+name = "either"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
+
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -105,6 +112,15 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25db6b064527c5d482d0423354fcd07a89a2dfe07b67892e62411946db7f07b0"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.150"

Cargo.toml

@@ -10,4 +10,5 @@ ariadne = "0.3"
 bit-vec = "0.6"
 chumsky = "0.9"
 indexmap = "2"
+itertools = "0.12"
 paste = "1"

src/bin/day5.rs

@@ -3,29 +3,158 @@
 
 use aoc23::read;
 use chumsky::{prelude::*, text::int};
+use itertools::Itertools as _;
+use std::{
+	fmt::{self, Debug, Display},
+	ops::{Add, Deref, DerefMut}
+};
 
-struct Range {
-	source_start: usize,
-	target_start: usize,
+trait Newtype:
+	Copy
+	+ Debug
+	+ Ord
+	+ From<usize>
+	+ Into<usize>
+	+ Deref<Target = usize>
+	+ DerefMut
+	+ Display
+	+ Add<usize, Output = Self>
+{
+}
+
+macro_rules! newtype {
+	($( struct $newtype:ident($inner:ident);)*) => {
+		$(
+			#[derive(Clone, Copy, Debug, Eq, PartialEq, PartialOrd, Ord)]
+			struct $newtype($inner);
+
+			impl From<$inner> for $newtype {
+				fn from(inner: $inner) -> Self {
+					Self(inner)
+				}
+			}
+
+			impl From<$newtype> for $inner {
+				fn from(newtype: $newtype) -> Self {
+					newtype.0
+				}
+			}
+
+			impl Deref for $newtype {
+				type Target = $inner;
+
+				fn deref(&self) -> &$inner {
+					&self.0
+				}
+			}
+
+			impl DerefMut for $newtype {
+				fn deref_mut(&mut self) -> &mut $inner {
+					&mut self.0
+				}
+			}
+
+			impl Display for $newtype {
+				fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+					write!(f, "{}", self.0)
+				}
+			}
+
+			impl Add<$inner> for $newtype {
+				type Output = $newtype;
+
+				fn add(self, rhs: $inner) -> Self {
+					Self(self.0 + rhs)
+				}
+			}
+
+			impl Newtype for $newtype {}
+		)*
+	};
+}
+
+newtype! {
+	struct Seed(usize);
+	struct Soil(usize);
+	struct Fertilizer(usize);
+	struct Water(usize);
+	struct Light(usize);
+	struct Temperature(usize);
+	struct Humidity(usize);
+	struct Location(usize);
+}
+
+#[derive(Debug)]
+struct Range<S, T> {
+	source_start: S,
+	target_start: T,
 	len: usize
 }
 
-struct Map {
-	ranges: Vec<Range>
+struct Map<S, T> {
+	ranges: Vec<Range<S, T>>
 }
 
-impl Map {
-	fn get(&self, source: usize) -> usize {
+impl<S, T> Map<S, T>
+where
+	S: Newtype,
+	T: Newtype
+{
+	fn get(&self, source: S) -> T {
 		for r in &self.ranges {
-			let Some(offset) = source.checked_sub(r.source_start) else {
+			let Some(offset) = source.checked_sub(r.source_start.into()) else {
 				continue;
 			};
 			if offset < r.len {
-				return r.target_start + offset;
+				return (r.target_start.into() + offset).into();
 			}
 		}
 
-		source
+		source.into().into()
+	}
+
+	fn get_range_impl(&self, start: S, len: usize) -> Vec<(T, usize)> {
+		let mut result = Vec::new();
+		for r in &self.ranges {
+			let possible_start = start.max(r.source_start);
+			let possible_end = (start + len).min(r.source_start + r.len);
+			if possible_start < possible_end {
+				let range = (
+					r.target_start + (possible_start.into() - r.source_start.into()),
+					possible_end.into() - possible_start.into()
+				);
+				// eprintln!("({start:?}, {len}) => {range:?} ({r:?}");
+				result.push(range);
+
+				if start < possible_start {
+					result.extend(
+						self.get_range_impl(start, possible_start.into() - start.into())
+					);
+				}
+				if (start + len) > possible_end {
+					result.extend(self.get_range_impl(
+						possible_end,
+						start.into() + len - possible_end.into()
+					));
+				}
+			}
+		}
+
+		if result.is_empty() {
+			result.push((start.into().into(), len));
+		}
+
+		result
+	}
+
+	fn get_range(&self, (start, len): (S, usize)) -> Vec<(T, usize)> {
+		let result = self.get_range_impl(start, len);
+
+		// for range in &result {
+		// 	eprintln!("({start:?}, {len}) => {range:?}");
+		// }
+
+		result
 	}
 
 	fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
@@ -38,8 +167,8 @@ impl Map {
 				ranges: ranges
 					.into_iter()
 					.map(|ints: Vec<String>| Range {
-						source_start: ints[1].parse().unwrap(),
-						target_start: ints[0].parse().unwrap(),
+						source_start: ints[1].parse::<usize>().unwrap().into(),
+						target_start: ints[0].parse::<usize>().unwrap().into(),
 						len: ints[2].parse().unwrap()
 					})
 					.collect()
@@ -48,25 +177,27 @@ impl Map {
 }
 
 struct Almanac {
-	seeds: Vec<usize>,
-	seed_to_soil: Map,
-	soil_to_fertilizer: Map,
-	fertilizer_to_water: Map,
-	water_to_light: Map,
-	light_to_temperature: Map,
-	temperature_to_humidity: Map,
-	humidity_to_location: Map
+	seeds: Vec<Seed>,
+	seed_to_soil: Map<Seed, Soil>,
+	soil_to_fertilizer: Map<Soil, Fertilizer>,
+	fertilizer_to_water: Map<Fertilizer, Water>,
+	water_to_light: Map<Water, Light>,
+	light_to_temperature: Map<Light, Temperature>,
+	temperature_to_humidity: Map<Temperature, Humidity>,
+	humidity_to_location: Map<Humidity, Location>
 }
 
 impl Almanac {
 	fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
-		fn parse_another_map<'a, P, T>(
+		fn parse_another_map<'a, P, R, S, T>(
 			parser: P,
 			name: &'a str
-		) -> impl Parser<char, (T, Map), Error = Simple<char>> + 'a
+		) -> impl Parser<char, (R, Map<S, T>), Error = Simple<char>> + 'a
 		where
-			P: Parser<char, T, Error = Simple<char>> + 'a,
-			T: 'a
+			P: Parser<char, R, Error = Simple<char>> + 'a,
+			R: 'a,
+			S: Newtype + 'a,
+			T: Newtype + 'a
 		{
 			parser
 				.then_ignore(just(name))
@@ -78,8 +209,8 @@ impl Almanac {
 			.ignore_then(int(10).separated_by(just(" ")))
 			.map(|ints: Vec<String>| {
 				ints.into_iter()
-					.map(|int| int.parse().unwrap())
-					.collect::<Vec<usize>>()
+					.map(|int| int.parse::<usize>().unwrap().into())
+					.collect::<Vec<Seed>>()
 			})
 			.then_ignore(just("\n\n"));
 		let parser = parse_another_map(parser, "seed-to-soil").then_ignore(just("\n"));
@@ -152,5 +283,23 @@ fn main() -> anyhow::Result<()> {
 		.unwrap();
 	println!("{min_loc}");
 
+	let min_loc = almanac
+		.seeds
+		.iter()
+		.copied()
+		.tuples()
+		.map(|(start, len)| (start, len.into()))
+		.flat_map(|range| almanac.seed_to_soil.get_range(range))
+		.flat_map(|range| almanac.soil_to_fertilizer.get_range(range))
+		.flat_map(|range| almanac.fertilizer_to_water.get_range(range))
+		.flat_map(|range| almanac.water_to_light.get_range(range))
+		.flat_map(|range| almanac.light_to_temperature.get_range(range))
+		.flat_map(|range| almanac.temperature_to_humidity.get_range(range))
+		.flat_map(|range| almanac.humidity_to_location.get_range(range))
+		.map(|(start, _)| start)
+		.min()
+		.unwrap();
+	println!("{min_loc}");
+
 	Ok(())
 }