aocpp/2017/11.cpp

#include <array>
#include <bit>
#include <cstdint>
#include <iostream>
#include <optional>
#include <string>
#include <vector>

#include <doctest.h>

#include <aocpp/Startup.hpp>
#include <aocpp/Parsing.hpp>
#include <aocpp/Hex.hpp>

using namespace aocpp;

namespace {

auto Walk(std::string const& commands)
-> std::pair<std::int64_t, std::int64_t>
{
  Hex here {};
  std::int64_t part2 = 0;
  for (auto const& command : aocpp::SplitOn(commands, ",")) {
    here +=
      "n"  == command ? HEX_N  :
      "ne" == command ? HEX_NE :
      "nw" == command ? HEX_NW :
      "s"  == command ? HEX_S  :
      "se" == command ? HEX_SE :
      "sw" == command ? HEX_SW :
      throw std::runtime_error{"bad input"};
    part2 = std::max(part2, hex_distance(here));
  }
  return {hex_distance(here), part2};
}

} // namespace

TEST_SUITE("2017-11 examples") {
  TEST_CASE("example 1") {
    auto [p1,p2] = Walk("ne,ne,ne");
    CHECK(p1 == 3);
    CHECK(p2 == 3);
  }
  TEST_CASE("example 2") {
    auto [p1,p2] = Walk("ne,ne,sw,sw");
    CHECK(p1 == 0);
    CHECK(p2 == 2);
  }
  TEST_CASE("example 3") {
    auto [p1,p2] = Walk("ne,ne,s,s");
    CHECK(p1 == 2);
    CHECK(p2 == 2);
  }
  TEST_CASE("example 4") {
    auto [p1,p2] = Walk("se,sw,se,sw,sw");
    CHECK(p1 == 3);
    CHECK(p2 == 3);
  }
}

auto Main(std::istream & in, std::ostream & out) -> void
{
  std::string line;
  std::getline(in, line);
  auto const [part1, part2] = Walk(line);
  out << "Part 1: " << part1 << std::endl;
  out << "Part 2: " << part2 << std::endl;
}