Advent of Code - Day 2

day.cpp

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

using namespace std;

struct Game {
  int r, g, b;
};

// for string delimiter
std::vector<std::string> split(std::string s, std::string delimiter) {
  size_t pos_start = 0, pos_end, delim_len = delimiter.length();
  std::string token;
  std::vector<std::string> res;

  while ((pos_end = s.find(delimiter, pos_start)) != std::string::npos) {
    token = s.substr(pos_start, pos_end - pos_start);
    pos_start = pos_end + delim_len;
    res.push_back(token);
  }

  res.push_back(s.substr(pos_start));
  return res;
}

// returns vector of game sets for each game string, i.e.
// from "Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green"
// it should return 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
vector<Game> parseGameSets(string str) {
  string setsStr = str.substr(str.find(":") + 1);
  vector<string> sets = split(setsStr, ";");
  vector<Game> gameSets;

  for (auto& s : sets) {
    vector<string> cubes = split(s, ",");
    Game gameSetObj{};

    for (auto& c : cubes) {
      stringstream strS(c);
      int count = 0;
      string type;
      strS >> count >> type;
      if (type == "red") {
        gameSetObj.r += count;
      }
      else if (type == "green") {
        gameSetObj.g += count;
      }
      else if (type == "blue") {
        gameSetObj.b += count;
      }
    }

    gameSets.push_back(gameSetObj);
  }

  return gameSets;
}

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

  if (!infile.is_open()) {
    cout << "File prob\n";
    return -1;
  }

  string line;
  unsigned long long sum = 0;
  int id = 1;
  while (infile.good()) {
    getline(infile, line);

    vector<Game> games = parseGameSets(line);
    
    int r, g, b;
    r = g = b = 0;

    for (auto& game : games) {
      r = max(r, game.r);
      g = max(g, game.g);
      b = max(b, game.b);
    }


    sum += r * g * b;

    id++;
  }

  cout << "Sum " << sum << "\n";
  infile.close();
}