Move c++ solutions into separate directory

2024/cpp/day-07/main.cpp

@@ -0,0 +1,99 @@
+#include <cmath>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+using namespace std;
+
+struct Equation
+{
+    long result;
+    vector<int> numbers;
+};
+
+void readInput(vector<Equation> &equations)
+{
+    string line;
+    while (getline(cin, line)) {
+        stringstream stream(line);
+        Equation equation;
+
+        string result;
+        getline(stream, result, ':');
+        equation.result = stol(result);
+
+        int number;
+        while (stream >> number) {
+            equation.numbers.push_back(number);
+        }
+
+        equations.push_back(equation);
+    }
+}
+
+long computeEquationResult(const vector<int> &numbers,
+                           size_t operatorMask,
+                           const size_t operatorSpace)
+{
+    long currentResult = numbers[0];
+
+    for (size_t operatorIndex = 0; operatorIndex < numbers.size() - 1; operatorIndex++) {
+        size_t numberIndex = operatorIndex + 1;
+
+        int currentOperator = (operatorMask / static_cast<int>(pow(operatorSpace, operatorIndex)))
+                              % operatorSpace;
+
+        switch (currentOperator) {
+        case 0:
+            currentResult += numbers[numberIndex];
+            break;
+        case 1:
+            currentResult *= numbers[numberIndex];
+            break;
+        case 2:
+            currentResult = stol(to_string(currentResult) + to_string(numbers[numberIndex]));
+        default:
+            break;
+        }
+    }
+
+    return currentResult;
+}
+
+bool isValidEquation(const Equation &equation, const size_t operatorSpace)
+{
+    const size_t operatorCount = equation.numbers.size() - 1;
+    const size_t maxOperatorMask = pow(operatorSpace, operatorCount) - 1;
+
+    for (size_t operatorMask = 0; operatorMask <= maxOperatorMask; operatorMask++) {
+        if (computeEquationResult(equation.numbers, operatorMask, operatorSpace)
+            == equation.result) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+int main()
+{
+    vector<Equation> equations;
+    readInput(equations);
+
+    long totalResult = 0;
+    long totalResultWithConcatenation = 0;
+    for (const Equation &equation : equations) {
+        if (isValidEquation(equation, 2)) {
+            totalResult += equation.result;
+            totalResultWithConcatenation += equation.result;
+        } else if (isValidEquation(equation, 3)) {
+            totalResultWithConcatenation += equation.result;
+        }
+    }
+
+    // Part one
+    cout << "Total calibration result: " << totalResult << endl;
+
+    // Part one
+    cout << "Total calibration result with concatenation: " << totalResultWithConcatenation << endl;
+}