aoc24/d3/main.cxx

61 lines
1.7 KiB
C++

#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;
}