aoc 2024 day 23

Author: TheCK

adventofcode/README.md

@@ -1454,7 +1454,7 @@
 [20232402tests]: src/test/java/org/ck/adventofcode/year2023/Day24Test.java
 [20232501tests]: src/test/java/org/ck/adventofcode/year2023/Day25Test.java
 
-# 2024 (44/49)
+# 2024 (46/49)
 
 |        # | Name                                                | Solution                             | Test                              |
 |---------:|-----------------------------------------------------|:------------------------------------:|:---------------------------------:|
@@ -1502,8 +1502,8 @@
 | 20242102 | [Day 21: Keypad Conundrum - Part 2][20242102]       | ✅[💾][20242102solution] | ✅[💾][20242102tests] |
 | 20242201 | [Day 22: Monkey Market][20242201]                   | ✅[💾][20242201solution] | ✅[💾][20242201tests] |
 | 20242202 | [Day 22: Monkey Market - Part 2][20242202]          | ✅[💾][20242202solution] | ✅[💾][20242202tests] |
-| 20242301 | [Day 23: ?][20242301]                               | [💾][20242301solution]        | [💾][20242301tests]        |
-| 20242302 | [Day 23: ? - Part 2][20242302]                      | [💾][20242302solution]        | [💾][20242302tests]        |
+| 20242301 | [Day 23: LAN Party][20242301]                       | ✅[💾][20242301solution] | ✅[💾][20242301tests] |
+| 20242302 | [Day 23: LAN Party - Part 2][20242302]              | ✅[💾][20242302solution] | ✅[💾][20242302tests] |
 | 20242401 | [Day 24: ?][20242401]                               | [💾][20242401solution]        | [💾][20242401tests]        |
 | 20242402 | [Day 24: ? - Part 2][20242402]                      | [💾][20242402solution]        | [💾][20242402tests]        |
 | 20242501 | [Day 25: ?][20242501]                               | [💾][20242501solution]        | [💾][20242501tests]        |

adventofcode/src/main/java/org/ck/adventofcode/year2024/Day23.java

@@ -1,34 +1,108 @@
 package org.ck.adventofcode.year2024;
 
-import java.util.Scanner;
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import org.ck.adventofcode.util.AOCSolution;
 import org.ck.codechallengelib.annotation.Solution;
 
 @Solution(
     id = 20242301,
-    name = "Day 23: ?",
+    name = "Day 23: LAN Party",
     url = "https://adventofcode.com/2024/day/23",
-    category = "2024",
-    solved = false)
+    category = "2024")
 @Solution(
     id = 20242302,
-    name = "Day 23: ? - Part 2",
+    name = "Day 23: LAN Party - Part 2",
     url = "https://adventofcode.com/2024/day/23#part2",
-    category = "2024",
-    solved = false)
+    category = "2024")
 public class Day23 extends AOCSolution {
 
   @Override
   protected void runPartOne(final Scanner in) {
-    run(in);
+    run(in, Day23::getGroupsOfThree);
   }
 
   @Override
   protected void runPartTwo(final Scanner in) {
-    run(in);
+    run(in, Day23::getLargestGroup);
   }
 
-  private void run(final Scanner in) {
-    print("Whoopsie");
+  private void run(final Scanner in, final Function<Map<String, Set<String>>, String> getResult) {
+    final Map<String, Set<String>> reachable = new HashMap<>();
+
+    while (in.hasNextLine()) {
+      final String[] names = in.nextLine().split("-");
+
+      reachable.computeIfAbsent(names[0], k -> new HashSet<>()).add(names[1]);
+      reachable.computeIfAbsent(names[1], k -> new HashSet<>()).add(names[0]);
+    }
+
+    print(getResult.apply(reachable));
+  }
+
+  private static String getGroupsOfThree(Map<String, Set<String>> reachable) {
+    final Set<String> tNames =
+        reachable.keySet().stream()
+            .filter(name -> name.startsWith("t"))
+            .collect(Collectors.toSet());
+
+    final Set<Set<String>> networks = new HashSet<>();
+
+    for (String tName : tNames) {
+      for (String second : reachable.get(tName)) {
+        for (String third : reachable.get(tName)) {
+          if (reachable.get(second).contains(third)) {
+            networks.add(Set.of(tName, second, third));
+          }
+        }
+      }
+    }
+
+    return String.valueOf(networks.size());
+  }
+
+  private static String getLargestGroup(Map<String, Set<String>> reachable) {
+    Set<String> largestNetwork = new HashSet<>();
+
+    for (String tName : reachable.keySet()) {
+      Set<String> network = new HashSet<>();
+      network.add(tName);
+
+      for (String second : reachable.get(tName)) {
+        for (String third : reachable.get(tName)) {
+          if (second.equals(third)) {
+            continue;
+          }
+
+          if (reachable.get(second).contains(third)) {
+            network.add(second);
+            network.add(third);
+          }
+        }
+      }
+
+      final Iterator<String> iterator = network.iterator();
+      while (iterator.hasNext()) {
+        final String name = iterator.next();
+
+        for (String other : network) {
+          if (name.equals(other)) {
+            continue;
+          }
+
+          if (!reachable.get(other).contains(name)) {
+            iterator.remove();
+            break;
+          }
+        }
+      }
+
+      if (network.size() > largestNetwork.size()) {
+        largestNetwork = network;
+      }
+    }
+
+    return largestNetwork.stream().sorted().collect(Collectors.joining(","));
   }
 }

adventofcode/src/test/java/org/ck/adventofcode/year2024/Day23Test.java

@@ -1,11 +1,9 @@
 package org.ck.adventofcode.year2024;
 
 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 Day23Test extends BaseAOCTest {
   @ParameterizedTest
   @ValueSource(strings = {"01a"})

adventofcode/src/test/resources/org/ck/adventofcode/year2024/day23/01.result.txt

@@ -0,0 +1 @@
+1337

adventofcode/src/test/resources/org/ck/adventofcode/year2024/day23/01.txt

@@ -0,0 +1 @@
+7

adventofcode/src/test/resources/org/ck/adventofcode/year2024/day23/01a.result.txt

@@ -0,0 +1,32 @@
+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

adventofcode/src/test/resources/org/ck/adventofcode/year2024/day23/01a.txt

@@ -0,0 +1 @@
+aw,fk,gv,hi,hp,ip,jy,kc,lk,og,pj,re,sr

adventofcode/src/test/resources/org/ck/adventofcode/year2024/day23/02.result.txt

@@ -0,0 +1 @@
+co,de,ka,ta