AOC 2025 day 8

Author: TheCK

adventofcode/README.md

@@ -1658,7 +1658,7 @@
 [20242402tests]: src/test/java/org/ck/adventofcode/year2024/Day24Test.java
 [20242501tests]: src/test/java/org/ck/adventofcode/year2024/Day25Test.java
 
-# 2025 (14/24)
+# 2025 (16/24)
 
 |        # | Name                                            | Solution                             | Test                              |
 |---------:|-------------------------------------------------|:------------------------------------:|:---------------------------------:|
@@ -1676,8 +1676,8 @@
 | 20250602 | [Day 6: Trash Compactor - Part 2][20250602]     | ✅[💾][20250602solution] | ✅[💾][20250602tests] |
 | 20250701 | [Day 7: Laboratories ][20250701]                | ✅[💾][20250701solution] | ✅[💾][20250701tests] |
 | 20250702 | [Day 7: Laboratories - Part 2][20250702]        | ✅[💾][20250702solution] | ✅[💾][20250702tests] |
-| 20250801 | [Day 8: ][20250801]                             | [💾][20250801solution]        | [💾][20250801tests]        |
-| 20250802 | [Day 8:  - Part 2][20250802]                    | [💾][20250802solution]        | [💾][20250802tests]        |
+| 20250801 | [Day 8: Playground][20250801]                   | ✅[💾][20250801solution] | ✅[💾][20250801tests] |
+| 20250802 | [Day 8: Playground - Part 2][20250802]          | ✅[💾][20250802solution] | ✅[💾][20250802tests] |
 | 20250901 | [Day 9: ][20250901]                             | [💾][20250901solution]        | [💾][20250901tests]        |
 | 20250902 | [Day 9:  - Part 2][20250902]                    | [💾][20250902solution]        | [💾][20250902tests]        |
 | 20251001 | [Day 10: ][20251001]                            | [💾][20251001solution]        | [💾][20251001tests]        |

adventofcode/src/main/java/org/ck/adventofcode/year2025/Day08.java

@@ -1,34 +1,136 @@
 package org.ck.adventofcode.year2025;
 
 import java.util.*;
+import java.util.function.ToLongBiFunction;
+import java.util.stream.LongStream;
 import org.ck.adventofcode.util.AOCSolution;
 import org.ck.codechallengelib.annotation.Solution;
 
 @Solution(
     id = 20250801,
-    name = "Day 8: ",
+    name = "Day 8: Playground",
     url = "https://adventofcode.com/2025/day/8",
-    category = "2025",
-    solved = false)
+    category = "2025")
 @Solution(
     id = 20250802,
-    name = "Day 8:  - Part 2",
+    name = "Day 8: Playground - Part 2",
     url = "https://adventofcode.com/2025/day/8#part2",
-    category = "2025",
-    solved = false)
+    category = "2025")
 public class Day08 extends AOCSolution {
 
   @Override
   protected void runPartOne(final Scanner in) {
-    run(in);
+    final int connections = Integer.parseInt(in.nextLine());
+
+    run(
+        in,
+        connections,
+        (networks, _) -> {
+          final Queue<Network> sortedNetworks =
+              new PriorityQueue<>(Comparator.comparing(Network::size).reversed());
+          sortedNetworks.addAll(networks);
+
+          return (long) sortedNetworks.poll().boxes().size()
+              * sortedNetworks.poll().boxes().size()
+              * sortedNetworks.poll().boxes().size();
+        });
   }
 
   @Override
   protected void runPartTwo(final Scanner in) {
-    run(in);
+    run(in, -1, (_, xCoordinates) -> xCoordinates.reduce(1, (a, b) -> a * b));
+  }
+
+  private void run(
+      final Scanner in,
+      int stopAfter,
+      final ToLongBiFunction<Set<Network>, LongStream> resultGetter) {
+    final Set<Box> boxes = new HashSet<>();
+    final Queue<Distance> distances = new PriorityQueue<>(Comparator.comparing(Distance::distance));
+
+    parseInput(in, boxes, distances);
+
+    final Set<Network> networks = new HashSet<>();
+    LongStream xCoordinates = null;
+    boolean continueLoop = true;
+    while (continueLoop) {
+      final Distance distance = distances.poll();
+      if (distance == null) {
+        throw new IllegalStateException("Distance is null");
+      }
+
+      final Set<Network> effectedNetworks = getEffectedNetworks(networks, distance);
+
+      if (effectedNetworks.isEmpty()) {
+        networks.add(new Network(distance.boxes()));
+      } else {
+        final HashSet<Box> merged = new HashSet<>(distance.boxes());
+
+        for (final Network effectedNetwork : effectedNetworks) {
+          merged.addAll(effectedNetwork.boxes());
+          networks.remove(effectedNetwork);
+        }
+
+        final Network newNetwork = new Network(merged);
+        networks.add(newNetwork);
+
+        if (newNetwork.size() == boxes.size()) {
+          xCoordinates = distance.boxes().stream().mapToLong(Box::x);
+          continueLoop = false;
+        }
+      }
+
+      if (--stopAfter == 0) {
+        continueLoop = false;
+      }
+    }
+
+    print(resultGetter.applyAsLong(networks, xCoordinates));
   }
 
-  private void run(final Scanner in) {
-    // not yet implemented
+  private static Set<Network> getEffectedNetworks(
+      final Set<Network> networks, final Distance distance) {
+    final Set<Network> effectedNetworks = new HashSet<>();
+
+    for (final Network network : networks) {
+      for (final Box box : distance.boxes()) {
+        if (network.boxes().contains(box)) {
+          effectedNetworks.add(network);
+        }
+      }
+    }
+    return effectedNetworks;
+  }
+
+  private void parseInput(final Scanner in, final Set<Box> boxes, final Queue<Distance> distances) {
+    while (in.hasNextLine()) {
+      final String[] line = in.nextLine().split(",");
+      final Box box =
+          new Box(Integer.parseInt(line[0]), Integer.parseInt(line[1]), Integer.parseInt(line[2]));
+
+      for (final Box other : boxes) {
+        distances.add(new Distance(Set.of(box, other), getDistance(box, other)));
+      }
+
+      boxes.add(box);
+    }
+  }
+
+  private double getDistance(final Box box, final Box other) {
+    final long dx = box.x - other.x;
+    final long dy = box.y - other.y;
+    final long dz = box.z - other.z;
+
+    return Math.sqrt((double) dx * dx + dy * dy + dz * dz);
+  }
+
+  private record Box(long x, long y, long z) {}
+
+  private record Distance(Set<Box> boxes, double distance) {}
+
+  private record Network(Set<Box> boxes) {
+    public int size() {
+      return boxes.size();
+    }
   }
 }

adventofcode/src/test/java/org/ck/adventofcode/year2025/Day08Test.java

@@ -1,11 +1,9 @@
 package org.ck.adventofcode.year2025;
 
 import org.ck.adventofcode.util.BaseAOCTest;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
-@Disabled
 class Day08Test extends BaseAOCTest {
   @ParameterizedTest
   @ValueSource(strings = {"01a"})

adventofcode/src/test/resources/org/ck/adventofcode/year2025/day08/01.result.txt

@@ -0,0 +1 @@
+123234

adventofcode/src/test/resources/org/ck/adventofcode/year2025/day08/01.txt

@@ -0,0 +1 @@
+40

adventofcode/src/test/resources/org/ck/adventofcode/year2025/day08/01a.result.txt

@@ -0,0 +1,21 @@
+10
+162,817,812
+57,618,57
+906,360,560
+592,479,940
+352,342,300
+466,668,158
+542,29,236
+431,825,988
+739,650,466
+52,470,668
+216,146,977
+819,987,18
+117,168,530
+805,96,715
+346,949,466
+970,615,88
+941,993,340
+862,61,35
+984,92,344
+425,690,689

adventofcode/src/test/resources/org/ck/adventofcode/year2025/day08/01a.txt

@@ -0,0 +1 @@
+9259958565

adventofcode/src/test/resources/org/ck/adventofcode/year2025/day08/02.result.txt

@@ -0,0 +1 @@
+25272