5th day

data/examples/05.txt

@@ -0,0 +1,33 @@
+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

src/bin/05.rs

@@ -0,0 +1,121 @@
+advent_of_code::solution!(5);
+
+type Seed = u64;
+
+struct MapPart {
+    min_source: u64,
+    max_source: u64,
+    min_target: u64,
+    max_target: u64,
+}
+
+struct Map(Vec<MapPart>);
+
+impl Map {
+    pub fn map(&self, s: u64) -> u64 {
+        for map_part in &self.0 {
+            if s >= map_part.min_source && s <= map_part.max_source {
+                return s - map_part.min_source + map_part.min_target;
+            }
+        }
+
+        s
+    }
+
+    pub fn map_reverse(&self, s: u64) -> u64 {
+        for map_part in &self.0 {
+            if s >= map_part.min_target && s <= map_part.max_target {
+                return s - map_part.min_target + map_part.min_source;
+            }
+        }
+
+        s
+    }
+}
+
+fn parse_data(input: &str) -> (Vec<Seed>, Vec<Map>) {
+    let mut parts = input.split("\n\n");
+
+    let seeds = parts.next().unwrap()[7..]
+        .split_ascii_whitespace()
+        .map(|x| x.parse().unwrap())
+        .collect();
+
+    let mut maps = vec![];
+    for part in parts {
+        let mut part_result = vec![];
+        for line in part.lines().skip(1) {
+            let tmp = line
+                .split_ascii_whitespace()
+                .map(|x| x.parse().unwrap())
+                .collect::<Vec<_>>();
+
+            part_result.push(MapPart {
+                min_source: tmp[1],
+                max_source: tmp[1] + tmp[2] - 1,
+                min_target: tmp[0],
+                max_target: tmp[0] + tmp[2] - 1,
+            })
+        }
+        maps.push(Map(part_result));
+    }
+
+    (seeds, maps)
+}
+
+pub fn part_one(input: &str) -> Option<u64> {
+    let (seeds, maps) = parse_data(input);
+
+    let result = seeds
+        .into_iter()
+        .map(|location| maps.iter().fold(location, |acc, map| map.map(acc)))
+        .min()
+        .unwrap();
+
+    Some(result)
+}
+
+pub fn part_two(input: &str) -> Option<u64> {
+    let (seeds, maps) = parse_data(input);
+
+    let mut seed_ranges = Vec::with_capacity(seeds.len() / 2);
+    for i in (0..seeds.len()).step_by(2) {
+        let start = seeds[i];
+        let end = seeds[i] + seeds[i + 1];
+
+        seed_ranges.push(start..end)
+    }
+
+    let result = (0..u64::MAX)
+        .map(|location| {
+            (
+                location,
+                maps.iter()
+                    .rev()
+                    .fold(location, |acc, map| map.map_reverse(acc)),
+            )
+        })
+        .filter(|(_, seed)| seed_ranges.iter().any(|x| x.contains(seed)))
+        .map(|(location, _)| location)
+        .next()
+        .unwrap();
+
+    Some(result)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(35));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(46));
+    }
+}