Implement 2025 - Day 8 - Part 2

2025/08.rs

@@ -35,7 +35,8 @@ fn main() {
 
     // println!("Distances\n{:#?}", distances);
 
-    for _ in 0..1000 {
+    let mut last_connection = None;
+    while box_circuits.len() < boxes.len() || circuits.len() > 1 {
         let (first, second, distance) = distances.pop().unwrap();
         println!("Connecting:\n\t{:?} <=> {:?}", first, second);
 
@@ -53,25 +54,36 @@ fn main() {
                     first_boxes.push(b);
                     box_circuits.insert(b, fc);
                 }
+
+                last_connection = Some((first, second));
             },
             (Some(fc), None) => {
                 circuits.get_mut(fc).unwrap().push(*second);
                 box_circuits.insert(*second, fc);
+
+                last_connection = Some((first, second));
             },
             (None, Some(sc)) => {
                 circuits.get_mut(sc).unwrap().push(*first);
                 box_circuits.insert(*first, sc);
+
+                last_connection = Some((first, second));
             },
             (None, None) => {
                 let circuit = circuits.insert(vec![*first, *second]);
                 box_circuits.insert(*first, circuit);
                 box_circuits.insert(*second, circuit);
 
-                println!("\tCreated Circuit: {:?}", circuit);
+                // println!("\tCreated Circuit: {:?}", circuit);
+                last_connection = Some((first, second));
             }
         };
     }
 
+    let last_connection = last_connection.unwrap();
+    println!("Last Connection: {:?}", last_connection);
+    println!("Last Connection Distance: {:?}", last_connection.0.0 * last_connection.1.0);
+
     let mut circuit_list: Vec<_> = circuits.iter().map(|(k, v)| (k, v.len())).collect();
     circuit_list.sort_by_key(|(_, v)| core::cmp::Reverse(*v));