Add solution for "Day 23: LAN Party", part 1

src/Graph.cpp

@@ -0,0 +1,46 @@
+// Solutions to the Advent Of Code 2024.
+// Copyright (C) 2024  Stefan Müller
+//
+// This program is free software: you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free Software
+// Foundation, either version 3 of the License, or (at your option) any later
+// version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <aoc/Graph.hpp>
+
+#include <memory>
+
+const std::map<std::string, std::shared_ptr<Vertex>>& Graph::getVertices() const
+{
+    return vertices_;
+}
+
+void Graph::addEdge(const std::string& vertexId1, const std::string& vertexId2)
+{
+    auto v1 = findOrAddVertex(vertexId1);
+    auto v2 = findOrAddVertex(vertexId2);
+    v1->addNeighbor(v2);
+    v2->addNeighbor(v1);
+}
+
+std::shared_ptr<Vertex> Graph::findOrAddVertex(const std::string& vertexId)
+{
+    auto iter = vertices_.find(vertexId);
+    if (iter != vertices_.end())
+    {
+        return (*iter).second;
+    }
+    else
+    {
+        auto v = std::make_shared<Vertex>(vertexId);
+        vertices_.insert({ vertexId, v });
+        return v;
+    }
+}

src/LanParty.cpp

@@ -0,0 +1,85 @@
+// Solutions to the Advent Of Code 2024.
+// Copyright (C) 2024  Stefan Müller
+//
+// This program is free software: you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free Software
+// Foundation, either version 3 of the License, or (at your option) any later
+// version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <aoc/LanParty.hpp>
+
+std::string LanParty::getPuzzleName() const
+{
+    return "Day 23: LAN Party";
+}
+
+std::string LanParty::getInputFileName() const
+{
+    return "lan_party.txt";
+}
+
+void LanParty::processDataLine(const std::string& line)
+{
+    lan_.addEdge(line.substr(0, 2), line.substr(3, 2));
+}
+
+void LanParty::finish()
+{
+    auto vertices = lan_.getVertices();
+    // This works as long as "ta" is present as a computername, otherwise we would have to use
+    // vertices.find_if().
+    auto iterTx = vertices.find(getFirstTxComputerName());
+    while (iterTx != vertices.end() && iterTx->second->getId() <= getLastTxComputerName())
+    {
+        countInterconnectedThreeSets(*iterTx->second);
+        iterTx++;
+    }
+}
+
+void LanParty::countInterconnectedThreeSets(const Vertex& vertexTx)
+{
+    auto neighborsOfTx = vertexTx.getNeighbors();
+    for (size_t i = 0; i < neighborsOfTx.size(); i++)
+    {
+        auto vertexA = neighborsOfTx[i].lock();
+        if (shallProcessVertex(*vertexA, vertexTx))
+        {
+            for (size_t j{ i + 1 }; j < neighborsOfTx.size(); j++)
+            {
+                auto vertexB = neighborsOfTx[j].lock();
+                if (shallProcessVertex(*vertexB, vertexTx))
+                {
+                    for (auto& neighborOfA : vertexA->getNeighbors())
+                    {
+                        if (vertexB == neighborOfA.lock())
+                        {
+                            part1++;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+bool LanParty::shallProcessVertex(const Vertex& vertexToCheck, const Vertex& vertexTx) const
+{
+    return (vertexToCheck.getId()[0] != 't' || vertexToCheck.getId() > vertexTx.getId());
+}
+
+const std::string LanParty::getFirstTxComputerName() const
+{
+    return "ta";
+}
+
+const std::string LanParty::getLastTxComputerName() const
+{
+    return "tz";
+}

src/Program.cpp

@@ -28,6 +28,7 @@
 #include <aoc/PrintQueue.hpp>
 #include <aoc/GuardGallivant.hpp>
 #include <aoc/HoofIt.hpp>
+#include <aoc/LanParty.hpp>
 
 void Program::run()
 {
@@ -52,6 +53,7 @@ void Program::runSolvers()
     runSolver<PrintQueue>(solverEngine);
     runSolver<GuardGallivant>(solverEngine);
     runSolver<HoofIt>(solverEngine);
+    runSolver<LanParty>(solverEngine);
 }
 
 std::vector<std::string> Program::getInputPaths() const

src/Vertex.cpp

@@ -0,0 +1,38 @@
+// Solutions to the Advent Of Code 2024.
+// Copyright (C) 2024  Stefan Müller
+//
+// This program is free software: you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free Software
+// Foundation, either version 3 of the License, or (at your option) any later
+// version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <aoc/Vertex.hpp>
+
+#include <memory>
+
+Vertex::Vertex(const std::string id)
+    : id_{ id }, neighbors_{}
+{
+}
+
+std::string Vertex::getId() const
+{
+    return id_;
+}
+
+const std::vector<std::weak_ptr<Vertex>>& Vertex::getNeighbors() const
+{
+    return neighbors_;
+}
+
+void Vertex::addNeighbor(const std::shared_ptr<Vertex>& neighbor)
+{
+    neighbors_.push_back(neighbor);
+}