Complete 2023 Day 5 Part 1

2023/day5/src/main.rs

@@ -1,9 +1,8 @@
 use std::collections::{HashMap, VecDeque};
 use std::ops::Range;
-use crate::DataType::Soil;
+use DataType::*;
 
 const FILE_STR: &'static str = include_str!("input.txt");
-const EXAMPLE_FILE_STR: &'static str = include_str!("example-input.txt");
 
 #[derive(Debug, PartialEq, Eq, Hash, Copy, Clone)]
 enum DataType {
@@ -20,14 +19,14 @@ enum DataType {
 impl DataType {
     fn try_from(s: &str) -> Option<Self> {
         match s {
-            "seed" => Some(Self::Seed),
-            "soil" => Some(Self::Soil),
-            "fertilizer" => Some(Self::Fertilizer),
-            "water" => Some(Self::Water),
-            "light" => Some(Self::Light),
-            "temperature" => Some(Self::Temperature),
-            "humidity" => Some(Self::Humidity),
-            "location" => Some(Self::Location),
+            "seed" => Some(Seed),
+            "soil" => Some(Soil),
+            "fertilizer" => Some(Fertilizer),
+            "water" => Some(Water),
+            "light" => Some(Light),
+            "temperature" => Some(Temperature),
+            "humidity" => Some(Humidity),
+            "location" => Some(Location),
             _ => None,
         }
     }
@@ -50,32 +49,16 @@ impl DataMap {
         }
     }
 
-    fn get_dest_idx(&self, src_value: u64) -> u64 {
-        let src_index = src_value.checked_sub(self.to_range.start);
-        let dest_index = if let Some(idx) = src_index {
-            self.from_range.start.checked_add(idx)
-        } else {
-            Some(src_value)
-        };
-
-        match dest_index {
-            Some(n) => n,
-            None => src_value,
+    fn get_dest_idx(&self, src_value: u64) -> Option<u64> {
+        if let Some(idx) = src_value.checked_sub(self.to_range.start) {
+            if let Some(new_idx) = self.from_range.start.checked_add(idx) {
+                if new_idx < self.from_range.end {
+                    return Some(new_idx);
+                }
+            }
         }
-    }
 
-    fn get_src_idx(&self, dest_value: u64) -> u64 {
-        let dest_index = dest_value.checked_sub(self.from_range.start);
-        let src_index = if let Some(idx) = dest_index {
-            self.to_range.start.checked_add(idx)
-        } else {
-            Some(dest_value)
-        };
-
-        match src_index {
-            Some(n) => n,
-            None => dest_value,
-        }
+        None
     }
 }
 
@@ -115,6 +98,7 @@ impl Almanac {
                 let (from, to) = (types[0], types[1]);
                 let mappings: Vec<DataMap> = lines
                     .into_iter()
+                    .filter(|l| l.len() > 0)
                     .map(|line| {
                         line.split_whitespace()
                             .map(|s| s.trim())
@@ -133,8 +117,21 @@ impl Almanac {
     }
 
     fn x_from_y(&self, x: DataType, y: DataType, search: u64) -> u64 {
-        let maps = self.maps.get(&(y, x)).expect(&format!("Missing mapping from {:?} to {:?}", x, y));
-        todo!();
+        let maps = self
+            .maps
+            .get(&(y, x))
+            .expect(&format!("Missing mapping from {:?} to {:?}", x, y));
+        let mut mapped_value: Vec<Option<u64>> = maps
+            .into_iter()
+            .map(|dm| dm.get_dest_idx(search))
+            .filter(|r| r.is_some())
+            .collect();
+
+        if mapped_value.is_empty() {
+            return search;
+        }
+
+        mapped_value.pop().unwrap().unwrap()
     }
 
     fn soil_from_seed(&self, seed: u64) -> u64 {
@@ -142,17 +139,73 @@ impl Almanac {
 
         self.x_from_y(Soil, Seed, seed)
     }
+
+    fn fertilizer_from_soil(&self, soil: u64) -> u64 {
+        self.x_from_y(Fertilizer, Soil, soil)
+    }
+
+    fn location_from_seed(&self, seed: u64) -> u64 {
+        let soil = self.soil_from_seed(seed);
+        let fert = self.fertilizer_from_soil(soil);
+        let water = self.x_from_y(Water, Fertilizer, fert);
+        let light = self.x_from_y(Light, Water, water);
+        let temp = self.x_from_y(Temperature, Light, light);
+        let humid = self.x_from_y(Humidity, Temperature, temp);
+
+        self.x_from_y(Location, Humidity, humid)
+    }
+
+    fn locations_from_seeds(&self) -> HashMap<u64, u64> {
+        self.seeds
+            .iter()
+            .map(|s| (*s, self.location_from_seed(*s)))
+            .collect()
+    }
+
+    fn lowest_seed_location(&self) -> u64 {
+        self.locations_from_seeds()
+            .iter()
+            .map(|(_, l)| *l)
+            .min()
+            .unwrap()
+    }
+}
+
+fn part_one() {
+    let almanac = Almanac::parse(FILE_STR);
+    println!("Part 1: Lowest seed location: {}", almanac.lowest_seed_location());
 }
 
 fn main() {
-    let almanac = Almanac::parse(EXAMPLE_FILE_STR);
-    let soil = almanac.soil_from_seed(79);
+    part_one();
 }
 
 #[cfg(test)]
 mod tests {
+    use crate::Almanac;
+    use std::collections::HashMap;
+
     const EXAMPLE_FILE_STR: &'static str = include_str!("example-input.txt");
 
     #[test]
-    fn test_parse() {}
+    fn test_location_from_seed() {
+        let almanac = Almanac::parse(EXAMPLE_FILE_STR);
+        assert_eq!(82, almanac.location_from_seed(79));
+        assert_eq!(43, almanac.location_from_seed(14));
+        assert_eq!(86, almanac.location_from_seed(55));
+        assert_eq!(35, almanac.location_from_seed(13));
+    }
+
+    #[test]
+    fn test_locations_from_seeds() {
+        let almanac = Almanac::parse(EXAMPLE_FILE_STR);
+        let expected = HashMap::from([(79, 82), (14, 43), (55, 86), (13, 35)]);
+        assert_eq!(expected, almanac.locations_from_seeds());
+    }
+
+    #[test]
+    fn test_lowest_seed_location() {
+        let almanac = Almanac::parse(EXAMPLE_FILE_STR);
+        assert_eq!(35, almanac.lowest_seed_location());
+    }
 }