#include <fstream>
#include <iostream>
#include <iterator>
#include <regex>
#include <string>
using namespace std;

string
read_file(string_view filename)
{
	fstream input{ filename };
	return { istream_iterator<char>{ input }, {} };
}

void
part1(const string& data)
{
	static const regex pattern(R"(mul\(\d{1,3},\d{1,3}\))");

	long sum = 0;
	for ( auto it = sregex_iterator(data.begin(), data.end(), pattern); it != sregex_iterator(); ++it ) {
		long lhs = 0;
		long rhs = 0;
		sscanf(it->str().c_str(), "mul(%ld,%ld)", &lhs, &rhs);
		sum += lhs * rhs;
	}
	cout << sum << endl;
}

void
part2(const string& data)
{
	static const regex pattern(R"(do\(\)|don't\(\)|mul\(\d{1,3},\d{1,3}\))");

	long sum   = 0;
	bool state = true;
	for ( auto it = sregex_iterator(data.begin(), data.end(), pattern); it != sregex_iterator(); ++it ) {
		if ( it->str() == "do()" ) {
			state = true;
		}
		else if ( it->str() == "don't()" ) {
			state = false;
		}
		else if ( state ) {
			long lhs = 0;
			long rhs = 0;
			sscanf(it->str().c_str(), "mul(%ld,%ld)", &lhs, &rhs);
			sum += lhs * rhs;
		}
	}
	cout << sum << endl;
}

int
main()
{
	auto data = read_file("data/day03.txt");
	part1(data);
	part2(data);
}