day8: some cleanups

README.md

@@ -1,6 +1,6 @@
 <!-- AOC TILES BEGIN -->
 <h1 align="center">
-  2025 - 14 ⭐ - Rust
+  2025 - 16 ⭐ - Rust
 </h1>
 <a href="src/day1.rs">
   <img src=".aoc_tiles/tiles/2025/01.png" width="161px">
@@ -23,4 +23,7 @@
 <a href="src/day7.rs">
   <img src=".aoc_tiles/tiles/2025/07.png" width="161px">
 </a>
+<a href="src/day8.rs">
+  <img src=".aoc_tiles/tiles/2025/08.png" width="161px">
+</a>
 <!-- AOC TILES END -->

src/day8.rs

@@ -10,7 +10,7 @@ struct Junction {
 
 fn distance(a: &Junction, b: &Junction) -> f64 {
     if a.pos == b.pos {
-        f64::MAX // ugh
+        0f64
     } else {
         (((a.pos.0 - b.pos.0).pow(2) + (a.pos.1 - b.pos.1).pow(2) + (a.pos.2 - b.pos.2).pow(2))
             as f64)
@@ -52,12 +52,13 @@ struct Circuits {
 }
 
 impl Circuits {
-    fn find_circuit(&self, junction: usize) -> Option<usize> {
+    fn find_circuit(&self, junction: usize) -> usize {
         self.circuits
             .iter()
             .enumerate()
             .find(|(_i, c)| c.contains(&junction))
             .map(|(i, _c)| i)
+            .unwrap()
     }
     fn merge_circuits(&mut self, a: usize, b: usize) {
         if a == b {
@@ -73,14 +74,7 @@ impl Circuits {
         let a_circuit = self.find_circuit(a);
         let b_circuit = self.find_circuit(b);
 
-        match (a_circuit, b_circuit) {
-            (None, None) => self.circuits.push(vec![a, b]), // both are unconnected
-            (Some(a_circuit), Some(b_circuit)) => {
-                self.merge_circuits(a_circuit, b_circuit); // both are already in circuits, merge them
-            }
-            (Some(a_circuit), None) => self.circuits[a_circuit].push(b), // one is in a circuit, so add the other to the existing circuit
-            (None, Some(b_circuit)) => self.circuits[b_circuit].push(a),
-        };
+        self.merge_circuits(a_circuit, b_circuit); // both are already in circuits, merge them
     }
 }
 
@@ -89,8 +83,8 @@ fn parse(input: &str) -> Circuits {
     let junctions = input.lines().map(|l| l.into()).collect_vec();
 
     Circuits {
+        circuits: Vec::from_iter((0..junctions.len()).map(|i| vec![i])),
         junctions,
-        circuits: Vec::new(),
     }
 }
 
@@ -100,8 +94,8 @@ fn part1_impl(input: &Circuits, n: usize) -> u64 {
         .junctions
         .iter()
         .enumerate()
-        .combinations(2)
-        .map(|p| (p[0].0, p[1].0, p[0].1.distance(p[1].1)))
+        .tuple_combinations()
+        .map(|((a_pos, a), (b_pos, b))| (a_pos, b_pos, a.distance(b)))
         .sorted_by(|a, b| a.2.partial_cmp(&b.2).unwrap())
         .take(n)
     {
@@ -127,7 +121,7 @@ fn part1(input: &Circuits) -> u64 {
 #[aoc(day8, part2)]
 fn part2(input: &Circuits) -> u64 {
     let mut circuits = input.clone();
-    circuits.circuits = Vec::from_iter((0..circuits.junctions.len()).map(|i| vec![i]));
+
     for (a, b, _d) in circuits
         .junctions
         .iter()