2023: Day 5

README.md

@@ -9,6 +9,7 @@ Thank you to [Eric Wastl](http://was.tl) for running this incredible yearly even
 - [Day 02: Cube Conundrum](aoc_2023/src/day_02.rs)
 - [Day 03: Gear Ratios](aoc_2023/src/day_03.rs)
 - [Day 04: Scratchcards](aoc_2023/src/day_04.rs)
+- [Day 05: If You Give A Seed A Fertilizer](aoc_2023/src/day_05.rs)
 
 ## [2022](https://adventofcode.com/2022) [![aoc_2022](https://github.com/Basicprogrammer10/advent-of-code/actions/workflows/aoc_2022.yml/badge.svg)](https://github.com/Basicprogrammer10/advent-of-code/actions/workflows/aoc_2022.yml)
 

aoc_2023/src/day_05.rs

@@ -0,0 +1,158 @@
+use common::{Answer, Solution};
+
+pub struct Day05;
+
+impl Solution for Day05 {
+    fn name(&self) -> &'static str {
+        "If You Give A Seed A Fertilizer"
+    }
+
+    fn part_a(&self, input: &str) -> Answer {
+        let seeds = parse(input);
+
+        let mut min = u32::MAX;
+        for mut seed in seeds.seeds {
+            for map in &seeds.maps {
+                seed = map.get(seed);
+            }
+            min = min.min(seed);
+        }
+
+        min.into()
+    }
+
+    fn part_b(&self, input: &str) -> Answer {
+        let seeds = parse(input);
+
+        let mut min = u32::MAX;
+        for seed in seeds.seeds.chunks_exact(2) {
+            for mut seed in seed[0]..seed[0] + seed[1] {
+                for map in &seeds.maps {
+                    seed = map.get(seed);
+                }
+
+                min = min.min(seed);
+            }
+        }
+
+        min.into()
+    }
+}
+
+#[derive(Debug)]
+struct Map {
+    ranges: Vec<Range>,
+}
+
+#[derive(Debug)]
+struct Range {
+    start: u32,
+    end: u32,
+    length: u32,
+}
+
+struct ParseResult {
+    maps: Vec<Map>,
+    seeds: Vec<u32>,
+}
+
+fn parse(input: &str) -> ParseResult {
+    let mut maps = Vec::new();
+
+    let mut sections = input.split("\n\n");
+
+    let seeds = sections
+        .next()
+        .unwrap()
+        .split_whitespace()
+        .skip(1)
+        .map(|s| s.parse().unwrap())
+        .collect();
+
+    for section in sections.into_iter().filter(|x| !x.is_empty()) {
+        let lines = section.lines();
+        let mut ranges = Vec::new();
+
+        for line in lines.skip(1) {
+            let mut parts = line.split_whitespace();
+
+            let end = parts.next().unwrap().parse().unwrap();
+            let start = parts.next().unwrap().parse().unwrap();
+            let length = parts.next().unwrap().parse().unwrap();
+
+            ranges.push(Range { start, end, length });
+        }
+
+        maps.push(Map { ranges });
+    }
+
+    ParseResult { maps, seeds }
+}
+
+impl Map {
+    fn get(&self, value: u32) -> u32 {
+        for range in &self.ranges {
+            if range.start <= value && value <= range.start + range.length {
+                let diff = value - range.start;
+                return range.end + diff;
+            }
+        }
+
+        value
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use common::Solution;
+    use indoc::indoc;
+
+    use super::Day05;
+
+    const CASE: &str = indoc! {"
+        seeds: 79 14 55 13
+
+        seed-to-soil map:
+        50 98 2
+        52 50 48
+
+        soil-to-fertilizer map:
+        0 15 37
+        37 52 2
+        39 0 15
+
+        fertilizer-to-water map:
+        49 53 8
+        0 11 42
+        42 0 7
+        57 7 4
+
+        water-to-light map:
+        88 18 7
+        18 25 70
+
+        light-to-temperature map:
+        45 77 23
+        81 45 19
+        68 64 13
+
+        temperature-to-humidity map:
+        0 69 1
+        1 0 69
+
+        humidity-to-location map:
+        60 56 37
+        56 93 4
+
+    "};
+
+    #[test]
+    fn part_a() {
+        assert_eq!(Day05.part_a(CASE), 35.into());
+    }
+
+    #[test]
+    fn part_b() {
+        assert_eq!(Day05.part_b(CASE), 46.into());
+    }
+}

aoc_2023/src/lib.rs

@@ -6,6 +6,7 @@ mod day_01;
 mod day_02;
 mod day_03;
 mod day_04;
+mod day_05;
 // [import_marker]
 
 #[rustfmt::skip]
@@ -14,5 +15,6 @@ pub const ALL: &[&dyn Solution] = &[
     &day_02::Day02,
     &day_03::Day03,
     &day_04::Day04,
+    &day_05::Day05,
     // [list_marker]
 ];