aocpp/2022/16.cpp

#include <cstdint>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <string>
#include <tuple>
#include <vector>
#include <map>
#include <bitset>

#include <boost/spirit/home/qi.hpp>
#include <boost/range/irange.hpp>

#include <doctest.h>

#include <aocpp/Startup.hpp>

namespace {

auto ShortestDistances(std::vector<std::vector<std::uint64_t>> & dist)
{
  auto const range = boost::irange(dist.size());
  for (auto const k : range) {
    for (auto const i : range) {
      for (auto const j : range) {
        auto const new_dist = dist[i][k] + dist[k][j];
        auto & old_dist = dist[i][j];
        if (old_dist > new_dist) old_dist = new_dist;
      }
    }
  }
}

struct RawRoom {
  std::string name;
  std::uint64_t flow;
  std::vector<std::string> connections;
};

struct Room {
  std::uint64_t flow;
  std::vector<std::uint64_t> connections;
};

auto Parse(std::istream & in) -> std::vector<RawRoom>
{
  std::vector<RawRoom> result;
  std::string line;
  while (std::getline(in, line)) {
    RawRoom room;
    using namespace boost::spirit;
    auto const name = qi::as_string[+qi::alpha];
    auto const room_description =
      "Valve " >>
      name [ ([&](auto n) { room.name = n; }) ] >>
      " has flow rate=" >>
      qi::ulong_long [ ([&](auto f) { room.flow = f; }) ] >>
      "; tunnel"  >> -qi::string("s") >>
      " lead"     >> -qi::string("s") >>
      " to valve" >> -qi::string("s") >>
      " " >>
      (name % ", ") [ ([&](auto c) { room.connections = c; }) ];

    if (!qi::parse(line.begin(), line.end(), room_description)) {
      throw std::runtime_error{"bad input line"};
    }
    result.emplace_back(std::move(room));
  }
  return result;
}

auto GenerateGraph(std::vector<RawRoom> const& raw_rooms) -> std::vector<Room>
{
  std::vector<Room> result;
  std::map<std::string, std::size_t> names;

  std::vector<std::vector<std::uint64_t>> distances(
    raw_rooms.size(), std::vector<std::uint64_t>(raw_rooms.size(), 100)); // todo max limit
  
  for (auto const i : boost::irange(raw_rooms.size())) {
    names[raw_rooms[i].name] = i;
  }

  for (auto const i : boost::irange(raw_rooms.size())) {
    auto & ds = distances[i];
    for (auto const& name : raw_rooms[i].connections) {
      ds[names[name]] = 1;
    }
  }

  ShortestDistances(distances);

  for (auto const i : boost::irange(raw_rooms.size())) {
    result.push_back({raw_rooms[i].flow, std::move(distances[i])});
  }

  return result;
}

using Valves = std::bitset<64>;

struct State {
  std::uint64_t time;
  std::uint64_t flow;
  std::size_t location;
  Valves valves;
};

auto Routes(std::vector<Room> const& rooms, std::uint64_t time) -> std::map<unsigned long long, std::uint64_t>
{
  std::vector<State> states { State{time, 0, 0, {}} };
  std::map<unsigned long long, std::uint64_t> result;
  
  while (!states.empty()) {
    auto state = states.back();
    states.pop_back();

    auto const& room = rooms[state.location];

    for (auto const i : boost::irange(rooms.size())) {
      auto valves = state.valves;
      if (valves[i]) { continue; }
      auto const flow = rooms[i].flow;
      if (flow == 0) { continue; }
      auto const cost = room.connections[i];
      if (cost >= state.time) { continue; }
      auto const time_ = state.time - cost - 1;
      
      valves[i] = true;
      auto const flow_ = state.flow + time_;

      if (result[valves.to_ullong()] < flow_) {
        result[valves.to_ullong()] = flow_;
      }

      states.push_back({ time_, state.flow + time_, i, valves});
    }
  }
  
  return result;
}

} // namespace

TEST_SUITE("2022-16 examples") {
  TEST_CASE("example") {
    std::istringstream in {
 
    };
  }
}

auto main(int argc, char** argv) -> int
{
  auto const input = Parse(*aocpp::Startup(argc, argv));
  auto const graph = GenerateGraph(input);
  auto const routes = Routes(graph, 30);
  
  std::uint64_t p1 = 0;
  for (auto const& kv : routes) {
    p1 = std::max(p1, kv.second);
  }

  std::cout << "Part 1: " << p1 << std::endl;
  //Part2(snapshots, std::cout << "Part 2:\n");
}