AOC-2024-Problem 3 Part 1

aoc-2024-3-1.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <ctype.h>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <sstream>
#include <regex>

using namespace std;

int main()
{
  ifstream infile("input.txt");

  if (!infile.is_open()) {
    cout << "File prob\n";
    return -1;
  }
  long long total = 0;
  string line;
  std::regex pattern(R"(mul\((\d+),(\d+)\))");
  while (infile.good()) {
    getline(infile, line);
    if (line.empty()) continue;
    
    auto begin = std::sregex_iterator(line.begin(), line.end(), pattern);
    auto end = std::sregex_iterator();

    for (auto it = begin; it != end; it++) {
      std::smatch match = *it;
      int x = std::stoi(match.str(1));
      int y = std::stoi(match.str(2));
      total += x * y;
    }
  }
  infile.close();
  std::cout << total << std::endl;
}