feat(23/2024): solve first part

Author: manhunto

readme.md

@@ -33,6 +33,7 @@
 | [Day 20: Race Condition](src/solutions/year2024/day20.rs)         |   ⭐⭐   |            7.355 |          280.627 |
 | [Day 21: Keypad Conundrum](src/solutions/year2024/day21.rs)       |   ⭐    |            0.454 |                - |
 | [Day 22: Monkey Market](src/solutions/year2024/day22.rs)          |   ⭐⭐   |           16.325 |          270.527 |
+| [Day 23: LAN Party](src/solutions/year2024/day23.rs)              |   ⭐    |            6.823 |                - |
 
 # 2023
 

src/solutions/year2024/day23.rs

@@ -1,10 +1,46 @@
 use crate::solutions::Solution;
+use std::collections::{HashMap, HashSet};
 
 pub struct Day23;
 
 impl Solution for Day23 {
-    fn part_one(&self, _input: &str) -> String {
-        String::from("0")
+    fn part_one(&self, input: &str) -> String {
+        let mut neighbours: HashMap<&str, Vec<&str>> = HashMap::new();
+
+        let connections: Vec<(&str, &str)> = input
+            .lines()
+            .map(|line| {
+                let (a, b) = line.split_once('-').unwrap();
+
+                neighbours.entry(a).or_default().push(b);
+                neighbours.entry(b).or_default().push(a);
+
+                (a, b)
+            })
+            .collect();
+
+        let mut sets: HashSet<[&str; 3]> = HashSet::new();
+
+        connections.iter().for_each(|(a, b)| {
+            let a_neighbours = neighbours.get(a).unwrap();
+            let b_neighbours = neighbours.get(b).unwrap();
+
+            let intersection: Vec<_> = a_neighbours
+                .iter()
+                .filter(|x| b_neighbours.contains(x))
+                .collect();
+
+            intersection.iter().for_each(|c| {
+                let mut set = [*a, *b, *c];
+                set.sort();
+                sets.insert(set);
+            });
+        });
+
+        sets.iter()
+            .filter(|set| set.iter().any(|c| c.starts_with("t")))
+            .count()
+            .to_string()
     }
 
     fn part_two(&self, _input: &str) -> String {
@@ -17,10 +53,41 @@ mod tests {
     use crate::solutions::year2024::day23::Day23;
     use crate::solutions::Solution;
 
-    const EXAMPLE: &str = r#""#;
+    const EXAMPLE: &str = r#"kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn"#;
 
     #[test]
     fn part_one_example() {
-        assert_eq!("0", Day23.part_one(EXAMPLE));
+        assert_eq!("7", Day23.part_one(EXAMPLE));
     }
 }