aocpp/2019/01.cpp

#include <algorithm>
#include <cstdint>
#include <iostream>
#include <fstream>
#include <iterator>
#include <vector>

#include <doctest.h>

#include <aocpp/Startup.hpp>

namespace {

auto fuel1(std::int64_t weight) -> std::int64_t {
  return weight / 3 - 2;
}

auto fuel2(std::int64_t weight) -> std::int64_t {
  std::int64_t total = 0;
  for(;;) {
    weight = fuel1(weight);
    if (weight <= 0) break;
    total += weight;
  }
  return total;
}

}

TEST_SUITE("documented examples") {

TEST_CASE("part 1") {
  REQUIRE(fuel1(12) == 2);
  REQUIRE(fuel1(14) == 2);
  REQUIRE(fuel1(1969) == 654);
  REQUIRE(fuel1(100756) == 33583);
}

TEST_CASE("part 2") {
  REQUIRE(fuel2(14) == 2);
  REQUIRE(fuel2(1969) == 966);
  REQUIRE(fuel2(100756) == 50346);
}

}

auto Main(std::istream & in, std::ostream & out) -> void
{
  std::int64_t weight;
  std::int64_t part1 = 0;
  std::int64_t part2 = 0;

  while (in >> weight) {
    part1 += fuel1(weight);
    part2 += fuel2(weight);
  }

  out << "Part 1: " << part1 << std::endl;
  out << "Part 2: " << part2 << std::endl;
}