#include "common/aoc.h"

namespace y2016::day20
{
  using Input = std::vector<std::pair<uint64_t, uint64_t>>;
  REGISTER_DAY(2016, Day20, Input, uint32_t);

  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 1, 3);
  REGISTER_TEST(2016, Day20, Input, 1, 19449262);
  REGISTER_TEST_EXAMPLE(2016, Day20, ExampleInput, 2, 2);
  REGISTER_TEST(2016, Day20, Input, 2, 119);

  READ_INPUT(input)
  {
    std::vector<std::pair<uint64_t, uint64_t>> vec;
    std::string str;
    while (getline(input, str))
    {
      std::pair<uint32_t, uint32_t> pair;
      std::stringstream ss{str};
      ss >> pair.first >> "-" >> pair.second;
      vec.emplace_back(pair);
    }
    std::sort(vec.begin(), vec.end());
    return vec;
  }

  OUTPUT1(input)
  {
    if (input.front().first != 0)
      return 0;

    for (int i = 0; i < input.size(); i++)
    {
      if (input[i].second + 1 < input[i + 1].first)
        return input[i].second + 1;
    }
    return 0;
  }

  OUTPUT2(input)
  {
    uint64_t allowed = input.front().first;
    uint64_t currentMax = input.front().second;
    for (int i = 1; i < input.size(); i++)
    {
      if (currentMax < input[i].first - 1)
      {
        allowed += input[i].first - currentMax - 1;
        currentMax = input[i].second;
      }
      else
      {
        currentMax = std::max(currentMax, input[i].second);
      }
    }
    uint32_t max = isExample ? 9 : std::numeric_limits<uint32_t>::max();
    allowed += max - currentMax;
    return allowed;
  }
}