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#include <fstream>
#include <iostream>
#include <map>
#include <set>
#include <sstream>
#include <string>
using namespace std;
struct Item {
Item() = default;
Item(size_t chip_floor, size_t generator_floor) // NOLINT
: chip_floor_{ chip_floor }
, generator_floor_{ generator_floor }
{
}
size_t chip_floor_;
size_t generator_floor_;
bool operator<(const Item& rhs) const
{
if ( chip_floor_ != rhs.chip_floor_ ) {
return chip_floor_ < rhs.chip_floor_;
}
return generator_floor_ < rhs.generator_floor_;
}
};
struct State {
explicit State(const vector<Item>& items)
: items_{ items }
{
}
[[nodiscard]]
bool is_valid() const
{
for ( size_t i = 0; i != items_.size(); ++i ) {
const auto chip_floor = items_[i].chip_floor_; // Etage des Mikrochips
if ( chip_floor == items_[i].generator_floor_ ) {
continue; // Mikrochip ist mit seinem Generator zusammen
}
// Prüfe, ob ein fremder Generator auf derselben Etage ist
for ( size_t j = 0; j != items_.size(); ++j ) {
if ( j != i && chip_floor == items_[j].generator_floor_ ) {
return false; // Ungültig: Mikrochip mit fremdem Generator ohne eigenen Generator
}
}
}
return true;
}
[[nodiscard]]
bool is_goal() const
{
for ( const auto& item: items_ ) {
if ( item.chip_floor_ != 3 || item.generator_floor_ != 3 ) {
return false;
}
}
return elevator_ == 3;
}
bool operator<(const State& rhs) const
{
if ( elevator_ != rhs.elevator_ ) {
return elevator_ < rhs.elevator_;
}
return items_ < rhs.items_;
}
size_t elevator_{};
vector<Item> items_;
};
namespace {
set<string>
split(const string& line, char sep)
{
set<string> parts;
stringstream input{ line };
for ( string part; getline(input, part, sep); ) {
parts.insert(part);
}
for ( const auto& word: { "The", "a", "floor", "and", "contains", "microchip",
"microchip.", "microchip,", "generator", "generator.", "generator,", "first",
"second", "third", "fourth", "nothing", "relevant." } ) {
parts.erase(word);
}
return parts;
}
vector<Item>
read_file(const filesystem::path& filename)
{
fstream input{ filename };
map<string, Item> data;
auto is_microchip = [](string_view item) {
return item.ends_with("-compatible");
};
string line;
for ( size_t floor = 0; getline(input, line); ++floor ) {
auto items = split(line, ' ');
for ( auto item: items ) {
if ( is_microchip(item) ) {
item = item.erase(item.find('-'));
data[item].chip_floor_ = floor;
}
else {
data[item].generator_floor_ = floor;
}
}
}
vector<Item> result;
result.reserve(data.size());
for ( const auto& item: data ) {
result.emplace_back(item.second);
}
return result;
}
int
part1(const State& initial)
{
queue<pair<State, int>> queue; // {Zustand, Schritte}
set<State> visited;
queue.emplace(initial, 0);
visited.insert(initial);
while ( !queue.empty() ) {
auto [current, steps] = queue.front();
queue.pop();
if ( current.is_goal() ) {
return steps;
}
// Mögliche Aufzugbewegungen: hoch oder runter
for ( int dir: { -1, 1 } ) {
auto new_elevator = current.elevator_ + size_t(dir);
if ( new_elevator < 0 || new_elevator > 3 ) {
continue;
}
// Wähle 1 oder 2 Objekte
vector<size_t> items_on_floor;
for ( size_t i = 0; i < current.items_.size(); ++i ) {
if ( current.items_[i].generator_floor_ == current.elevator_ ) {
items_on_floor.emplace_back(i * 2); // Generator
}
if ( current.items_[i].chip_floor_ == current.elevator_ ) {
items_on_floor.emplace_back((i * 2) + 1); // Mikrochip
}
}
// Alle Kombinationen von 1 oder 2 Objekten
for ( size_t i = 0; i < items_on_floor.size(); ++i ) {
// 1 Objekt
State next = current;
next.elevator_ = new_elevator;
auto item = items_on_floor[i];
if ( item % 2 == 0 ) {
next.items_[item / 2].generator_floor_ = new_elevator; // Generator
}
else {
next.items_[item / 2].chip_floor_ = new_elevator; // Mikrochip
}
if ( next.is_valid() && !visited.contains(next) ) {
visited.emplace(next);
queue.emplace(next, steps + 1);
}
// 2 Objekte
for ( size_t j = i + 1; j < items_on_floor.size(); ++j ) {
State next2 = current;
next2.elevator_ = new_elevator;
auto item1 = items_on_floor[i];
auto item2 = items_on_floor[j];
if ( item1 % 2 == 0 ) {
next2.items_[item1 / 2].generator_floor_ = new_elevator;
}
else {
next2.items_[item1 / 2].chip_floor_ = new_elevator;
}
if ( item2 % 2 == 0 ) {
next2.items_[item2 / 2].generator_floor_ = new_elevator;
}
else {
next2.items_[item2 / 2].chip_floor_ = new_elevator;
}
if ( next2.is_valid() && !visited.contains(next2) ) {
visited.insert(next2);
queue.emplace(next2, steps + 1);
}
}
}
}
}
return -1; // Keine Lösung gefunden
}
int
part2(State initial)
{
initial.items_.emplace_back(0, 0);
initial.items_.emplace_back(0, 0);
return part1(initial);
}
} // namespace
int
main()
{
auto floors = read_file("data/day11.txt");
State state{ floors };
cout << "Part1: " << part1(state) << '\n';
cout << "Part2: " << part2(state) << '\n';
}
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