Rename single digit days

d03/main.cxx

@@ -0,0 +1,61 @@
+#include <iostream>
+#include <regex>
+
+using std::cout, std::endl;
+
+constexpr const char content[] = {
+    #embed "input.txt"
+};
+
+int part_1() {
+    std::string input = std::string(content);
+
+    auto acc{0};
+    std::regex re{"mul\\((\\d+),(\\d+)\\)"};
+    std::smatch match;
+
+    while (std::regex_search(input, match, re)) {
+        int a = std::stoi(match[1].str());
+        int b = std::stoi(match[2].str());
+        acc += a * b;
+
+        input = match.suffix().str(); 
+    } 
+
+    return acc;
+}
+
+int part_2() {
+    std::string input = std::string(content);
+
+    auto acc{0};
+    std::regex re{"do\\(\\)|don't\\(\\)|mul\\((\\d+),(\\d+)\\)"};
+    std::smatch match;
+    bool enabled{true};
+
+    while(std::regex_search(input, match, re)) {
+        if (match[0].str() == "do()") {
+            enabled = true;
+        } else if (match[0].str() == "don't()") {
+            enabled = false;
+        } else if (enabled) {
+                int x = std::stoi(match[1].str());
+                int y = std::stoi(match[2].str());
+                acc += x * y;
+        } 
+        input = match.suffix().str();
+    }
+    
+    return acc;
+} 
+
+int main() {
+    std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
+    auto p1_val = part_1();
+    std::chrono::steady_clock::time_point middle = std::chrono::steady_clock::now();
+    auto p2_val = part_2();
+    std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
+    cout << "Part 1: " << p1_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(middle - begin).count() << "µs)" << endl;  
+    cout << "Part 2: " << p2_val << " (" << std::chrono::duration_cast<std::chrono::microseconds>(end - middle).count() << "µs)" << endl;
+    return 0;
+}