day 5

README.md

@@ -24,6 +24,7 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | [Day 2](./src/bin/02.rs) | `117.1µs` | `205.3µs` |
 | [Day 3](./src/bin/03.rs) | `115.1µs` | `148.7µs` |
 | [Day 4](./src/bin/04.rs) | `81.9µs` | `51.3µs` |
+| [Day 5](./src/bin/05.rs) | `379.0µs` | `816.9µs` |
 
-**Total: 0.82ms**
+**Total: 2.01ms**
 <!--- benchmarking table --->

data/examples/05.txt

@@ -0,0 +1,28 @@
+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47

src/bin/04.rs

@@ -227,12 +227,12 @@ mod tests {
     #[test]
     fn test_part_one() {
         let result = part_one(&advent_of_code::template::read_file("examples", DAY));
-        assert_eq!(result, None);
+        assert_eq!(result, Some(18));
     }
 
     #[test]
     fn test_part_two() {
         let result = part_two(&advent_of_code::template::read_file("examples", DAY));
-        assert_eq!(result, None);
+        assert_eq!(result, Some(9));
     }
 }

src/bin/05.rs

@@ -0,0 +1,119 @@
+use std::{
+    cmp::Ordering,
+    collections::{HashMap, HashSet, VecDeque},
+};
+
+use itertools::Itertools;
+
+advent_of_code::solution!(5);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let (rules, updates) = input.split_once("\n\n").unwrap();
+
+    let rule_lookup =
+        rules
+            .lines()
+            .fold(HashMap::new(), |mut acc: HashMap<&str, Vec<&str>>, line| {
+                let (l, r) = line.split_once("|").unwrap();
+                acc.entry(l).or_default().push(r);
+                acc
+            });
+
+    let mut result = 0;
+    for update in updates.lines() {
+        let mut already_seen: HashSet<&str> = HashSet::new();
+        let mut success = true;
+        for value in update.split(',') {
+            let Some(must_come_after) = rule_lookup.get(value) else {
+                already_seen.insert(value);
+                continue;
+            };
+            let breaks_rule = must_come_after.iter().any(|val| already_seen.contains(val));
+            if breaks_rule {
+                success = false;
+                break;
+            }
+
+            already_seen.insert(value);
+        }
+
+        if success {
+            let as_strs = update.split(",").collect_vec();
+            let middle = as_strs[(as_strs.len() - 1) / 2].parse::<u32>().unwrap();
+            result += middle;
+        }
+    }
+
+    Some(result)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let (rules, updates) = input.split_once("\n\n").unwrap();
+
+    let rule_lookup =
+        rules
+            .lines()
+            .fold(HashMap::new(), |mut acc: HashMap<&str, Vec<&str>>, line| {
+                let (l, r) = line.split_once("|").unwrap();
+                acc.entry(l).or_default().push(r);
+                acc
+            });
+
+    let mut incorrect = vec![];
+    for update in updates.lines() {
+        let mut already_seen: HashSet<&str> = HashSet::new();
+        for value in update.split(',') {
+            let Some(must_come_after) = rule_lookup.get(value) else {
+                already_seen.insert(value);
+                continue;
+            };
+            let breaks_rule = must_come_after.iter().any(|val| already_seen.contains(val));
+            if breaks_rule {
+                incorrect.push(update);
+                break;
+            }
+
+            already_seen.insert(value);
+        }
+    }
+
+    let mut res = 0;
+    for update in incorrect.into_iter() {
+        let ordered = update
+            .split(",")
+            .sorted_by(|a, b| {
+                if !rule_lookup.contains_key(a) {
+                    return Ordering::Greater;
+                }
+
+                if rule_lookup[a].contains(b) {
+                    return Ordering::Less;
+                }
+
+                Ordering::Greater
+            })
+            .collect_vec();
+
+        let middle = ordered[(ordered.len() - 1) / 2].parse::<u32>().unwrap();
+        res += middle;
+    }
+
+    Some(res)
+}
+
+#[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(143));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(123));
+    }
+}