Day 5

src/day4/mod.rs

@@ -6,14 +6,14 @@ use crate::utils::Day;
 pub struct Day4 {
     pub input: String,
     pub acc: usize,
-    pub cards: HashMap::<usize /* Card # */, Vec<usize> /* (won card indexes) */>
+    pub cards: HashMap<usize /* Card # */, Vec<usize> /* (won card indexes) */>,
 }
 
 impl Day4 {
     fn recurse(&mut self, cards: &Vec<usize>) {
         for card in cards {
             self.acc += 1;
-            
+
             if let Some(won_cards) = self.cards.get(card) {
                 self.recurse(&won_cards.clone())
             }
@@ -24,7 +24,7 @@ impl Day4 {
 impl Day for Day4 {
     fn part1(&mut self) -> String {
         let mut sum = 0usize;
-        
+
         for line in self.input.lines() {
             let (winning, numbers) = line.split_once(": ").unwrap().1.split_once(" | ").unwrap();
             let winning = winning.split_whitespace().collect::<Vec<_>>();
@@ -37,7 +37,10 @@ impl Day for Day4 {
             }
 
             if winning_numbers.len() != 0 {
-                sum += winning_numbers.iter().skip(1).fold(1usize, |acc, _| acc * 2);
+                sum += winning_numbers
+                    .iter()
+                    .skip(1)
+                    .fold(1usize, |acc, _| acc * 2);
             }
         }
 
@@ -57,7 +60,14 @@ impl Day for Day4 {
                 }
             }
 
-            self.cards.insert(i + 1, winning_numbers.into_iter().enumerate().map(|(j, _)| (i + 1) + (j + 1)).collect());
+            self.cards.insert(
+                i + 1,
+                winning_numbers
+                    .into_iter()
+                    .enumerate()
+                    .map(|(j, _)| (i + 1) + (j + 1))
+                    .collect(),
+            );
         }
 
         self.recurse(&self.cards.keys().map(|e| *e).collect::<Vec<_>>());
@@ -98,9 +108,9 @@ Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
 Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
 Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11"#
                 .to_string(),
-                acc: 0usize,
+            acc: 0usize,
-                cards: HashMap::new()
+            cards: HashMap::new()
         }
         .solve(2));
     }
-}
+}

src/day5/mod.rs

@@ -0,0 +1,233 @@
+use std::collections::HashMap;
+
+use crate::utils::Day;
+
+#[derive(Debug)]
+pub struct Day5 {
+    pub input: String,
+}
+
+impl Day for Day5 {
+    fn part1(&mut self) -> String {
+        let groups = self.input.split("\n\n").skip(1).map(|g| {
+            let mut lines = g.lines();
+            (lines.next().unwrap(), lines.collect::<Vec<_>>())
+        });
+
+        let seeds = self
+            .input
+            .lines()
+            .next()
+            .unwrap()
+            .split_once(": ")
+            .unwrap()
+            .1
+            .split_whitespace()
+            .map(|s| s.parse::<usize>().unwrap());
+        let groups = groups
+            .map(|(name, list)| {
+                (
+                    name.split_once(' ').unwrap().0.split_once("-to-").unwrap(),
+                    list.into_iter().map(|line| {
+                        let nums = line.split_whitespace()
+                            .map(|n| n.parse::<usize>().unwrap())
+                            .collect::<Vec<_>>();
+                        (nums[0], nums[1], nums[2])
+                    }).collect::<Vec<_>>(),
+                )
+            })
+            .map(|((from, to), mappings)| (
+                from,
+                (
+                    to,
+                    mappings
+                )
+            ))
+            .collect::<HashMap<&str, (&str, Vec<(usize, usize, usize)>)>>();
+
+        let mut locations = Vec::<usize>::new();
+
+        for seed in seeds {
+            let (mut category, mut value) = ("seed", seed);
+            while category != "location" {
+                let (new_category, mappings) = groups.get(category).unwrap();
+                category = new_category;
+
+                for (destination_start, source_start, length) in mappings {
+                    if (source_start..&(source_start + length)).contains(&&value) {
+                        let delta = *source_start as isize - *destination_start as isize;
+                        value = (value as isize - delta) as usize;
+                        break;
+                    }
+                }
+            }
+
+            locations.push(value)
+        }
+
+        locations.into_iter().min().unwrap().to_string()
+    }
+
+    /// Yes my solution was to brute force it
+    /// Yes it worked
+    /// Yes it only took 13m and 31s to solve
+    /// No I will not elaborate on why I felt the need to do it this way
+    /// Yes I should probably solve it correctly at some point
+    fn part2(&mut self) -> String {
+        let groups = self.input.split("\n\n").skip(1).map(|g| {
+            let mut lines = g.lines();
+            (lines.next().unwrap(), lines.collect::<Vec<_>>())
+        });
+
+        let seeds = self
+            .input
+            .lines()
+            .next()
+            .unwrap()
+            .split_once(": ")
+            .unwrap()
+            .1
+            .split_whitespace()
+            .map(|s| s.parse::<usize>().unwrap())
+            .collect::<Vec<usize>>();
+        let seeds = seeds
+            .as_slice()
+            .chunks(2);
+
+        let groups = groups
+            .map(|(name, list)| {
+                (
+                    name.split_once(' ').unwrap().0.split_once("-to-").unwrap(),
+                    list.into_iter().map(|line| {
+                        let nums = line.split_whitespace()
+                            .map(|n| n.parse::<usize>().unwrap())
+                            .collect::<Vec<_>>();
+                        (nums[0], nums[1], nums[2])
+                    }).collect::<Vec<_>>(),
+                )
+            })
+            .map(|((from, to), mappings)| (
+                from,
+                (
+                    to,
+                    mappings
+                )
+            ))
+            .collect::<HashMap<&str, (&str, Vec<(usize, usize, usize)>)>>();
+
+        let mut location = 100000000usize;
+        let seedslen = seeds.len();
+
+        for (i, chunk) in seeds.enumerate() {
+            let (initial, range) = (chunk[0], chunk[1]);
+            for (j, seed) in (initial..(initial + range)).enumerate() {
+                if j % 1000 == 0 {
+                    println!("Chunk {}/{}, Seed {}/{} ({:.2}%)", i, seedslen, j, range, j as f64 / range as f64 * 100.0);
+                }
+                let (mut category, mut value) = ("seed", seed);
+                while category != "location" {
+                    let (new_category, mappings) = groups.get(category).unwrap();
+                    category = new_category;
+    
+                    for (destination_start, source_start, length) in mappings {
+                        if (source_start..&(source_start + length)).contains(&&value) {
+                            let delta = *source_start as isize - *destination_start as isize;
+                            value = (value as isize - delta) as usize;
+                            break;
+                        }
+                    }
+                }
+    
+                if location > value { location = value }
+            }
+        }
+
+        location.to_string()
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use crate::{day5::Day5, utils::Day};
+
+    #[test]
+    fn passes_example_1() {
+        dbg!(Day5 {
+            input: r#"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"#.to_string(),
+        }
+        .solve(1));
+    }
+
+    #[test]
+    fn passes_example_2() {
+        dbg!(Day5 {
+            input: r#"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"#.to_string(),
+        }
+        .solve(2));
+    }
+}

src/main.rs

@@ -6,12 +6,13 @@ use std::{
 
 use clap::{Parser, Subcommand};
 
-use crate::{day1::Day1, day2::Day2, day3::Day3, day4::Day4, utils::Day};
+use crate::{day1::Day1, day2::Day2, day3::Day3, day4::Day4, day5::Day5, utils::Day};
 
 pub mod day1;
 pub mod day2;
 pub mod day3;
 pub mod day4;
+pub mod day5;
 pub mod fetcher;
 pub mod utils;
 
@@ -91,6 +92,7 @@ async fn main() {
                     acc: 0usize,
                     cards: HashMap::new(),
                 }),
+                5 => Box::new(Day5 { input: response }),
                 _ => panic!("Invalid day #"),
             };
             let start = std::time::Instant::now();
@@ -140,6 +142,7 @@ async fn main() {
                     acc: 0usize,
                     cards: HashMap::new(),
                 }),
+                5 => Box::new(Day5 { input: response }),
                 _ => panic!("Invalid day #"),
             };
             let mut timings = Vec::<Duration>::new();