Add solution for "Day 24: Crossed Wires", part 1

src/CrossedWires.cpp

@@ -0,0 +1,160 @@
+// Solutions to the Advent Of Code 2024.
+// Copyright (C) 2025  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/CrossedWires.hpp>
+
+#include <sstream>
+
+CrossedWires::CrossedWires(const int inputFileNameSuffix)
+    : Solver(inputFileNameSuffix), isProcessingInputWires_{ true }, wires_{}, unevaluatedGates_{}, z_{ 0 }
+{
+}
+
+const std::string CrossedWires::getPuzzleName() const
+{
+    return "Crossed Wires";
+}
+
+const int CrossedWires::getPuzzleDay() const
+{
+    return 24;
+}
+
+void CrossedWires::processDataLine(const std::string& line)
+{
+    if (isProcessingInputWires_)
+    {
+        if (line.empty())
+        {
+            isProcessingInputWires_ = false;
+        }
+        else
+        {
+            processInputWire(line);
+        }
+    }
+    else
+    {
+        processLogicGate(line);
+    }
+}
+
+void CrossedWires::finish()
+{
+    while (!unevaluatedGates_.empty())
+    {
+        unevaluatedGates_.remove_if([this](const LogicGate& gate) { return tryEvaluateLogicGate(gate); });
+    }
+    part1 = z_.to_ullong();
+}
+
+constexpr char CrossedWires::getInputWireDelimiter()
+{
+    return ':';
+}
+
+constexpr char CrossedWires::getOutputWiresChar()
+{
+    return 'z';
+}
+
+void CrossedWires::processInputWire(const std::string& line)
+{
+    std::istringstream stream{ line };
+    std::string wire;
+    int value;
+    std::getline(stream, wire, getInputWireDelimiter());
+    stream >> value;
+
+    wires_.insert({ wire, value == 1 });
+}
+
+void CrossedWires::processLogicGate(const std::string& line)
+{
+    std::istringstream stream{ line };
+    LogicGate gate;
+    stream >> gate;
+
+    if (!tryEvaluateLogicGate(gate))
+    {
+        unevaluatedGates_.push_front(gate);
+    }
+}
+
+bool CrossedWires::tryEvaluateLogicGate(const LogicGate& gate)
+{
+    auto in1 = wires_.find(gate.inputWire1);
+    if (in1 != wires_.end())
+    {
+        if (in1->second)
+        {
+            if (gate.kind == LogicGate::Kind::Or)
+            {
+                setOutputWire(gate.outputWire, true);
+                return true;
+            }
+        }
+        else if (gate.kind == LogicGate::Kind::And)
+        {
+            setOutputWire(gate.outputWire, false);
+            return true;
+        }
+    }
+
+    auto in2 = wires_.find(gate.inputWire2);
+    if (in2 != wires_.end())
+    {
+        if (in2->second)
+        {
+            if (gate.kind == LogicGate::Kind::Or)
+            {
+                setOutputWire(gate.outputWire, true);
+                return true;
+            }
+        }
+        else if (gate.kind == LogicGate::Kind::And)
+        {
+            setOutputWire(gate.outputWire, false);
+            return true;
+        }
+        if (in1 != wires_.end())
+        {
+            switch (gate.kind)
+            {
+                case LogicGate ::Kind ::And :
+                    setOutputWire(gate.outputWire, true);
+                    return true;
+                case LogicGate ::Kind ::Or :
+                    setOutputWire(gate.outputWire, false);
+                    return true;
+                case LogicGate ::Kind ::Xor :
+                    setOutputWire(gate.outputWire, in1->second != in2->second);
+                    return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+void CrossedWires::setOutputWire(const std::string& wire, const bool value)
+{
+    if (wire[0] == getOutputWiresChar())
+    {
+        size_t index = std::stoull(wire.substr(1, 2));
+        z_[index] = value;
+    }
+    wires_.insert({ wire, value });
+}

src/Program.cpp

@@ -44,6 +44,7 @@
 #include <aoc/KeypadConundrum.hpp>
 #include <aoc/MonkeyMarket.hpp>
 #include <aoc/LanParty.hpp>
+#include <aoc/CrossedWires.hpp>
 
 void Program::run()
 {
@@ -84,6 +85,7 @@ void Program::runSolvers()
     runSolver<KeypadConundrum>(solverEngine);
     runSolver<MonkeyMarket>(solverEngine);
     runSolver<LanParty>(solverEngine);
+    runSolver<CrossedWires>(solverEngine);
 }
 
 std::vector<std::string> Program::getInputPaths() const

src/common/LogicGate.cpp

@@ -0,0 +1,45 @@
+// Solutions to the Advent Of Code 2024.
+// Copyright (C) 2025  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/common/LogicGate.hpp>
+
+std::istream& operator>>(std::istream& is, LogicGate& logicGate)
+{
+    std::string token;
+    is >> logicGate.inputWire1 >> logicGate.kind >> logicGate.inputWire2 >> token >> logicGate.outputWire;
+    return is;
+}
+
+std::istream& operator>>(std::istream& is, LogicGate::Kind& kind)
+{
+    std::string s;
+    is >> s;
+    switch (s[0])
+    {
+        case 'A' :
+            kind = LogicGate::Kind::And;
+            break;
+        case 'O' :
+            kind = LogicGate::Kind::Or;
+            break;
+        case 'X' :
+            kind = LogicGate::Kind::Xor;
+            break;
+        default :
+            kind = LogicGate::Kind::Unknown;
+            break;
+    }
+    return is;
+}