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#include <filesystem>
#include <fstream>
#include <iostream>
#include <map>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
namespace {
vector<string>
split(const string& line)
{
stringstream strm{ line };
vector<string> words;
for ( string word; getline(strm, word, ' '); ) {
words.emplace_back(word);
}
return words;
}
map<string, set<string>>
read_file(const filesystem::path& filename)
{
ifstream file{ filename };
map<string, set<string>> graph;
for ( string line; getline(file, line); ) {
auto words = split(line);
graph[words.at(1)].emplace(words.at(7));
}
return graph;
}
vector<string>
topologicalSort(const map<string, set<string>>& graph)
{
map<string, int> indegree;
// Eingangsgrade initialisieren
for ( const auto& [node, neighbors]: graph ) {
if ( !indegree.contains(node) ) {
indegree[node] = 0;
}
for ( const auto& neighbor: neighbors ) {
indegree[neighbor]++;
}
}
// Queue mit Knoten, deren Eingangsgrad 0 ist
priority_queue<string, vector<string>, greater<>> queue;
for ( const auto& [node, deg]: indegree ) {
if ( deg == 0 ) {
queue.push(node);
}
}
vector<string> sorted;
// Kahn's Algorithmus
while ( !queue.empty() ) {
string node = queue.top();
queue.pop();
sorted.push_back(node);
if ( !graph.contains(node) ) {
continue;
}
for ( const auto& neighbor: graph.at(node) ) {
indegree[neighbor]--;
if ( indegree[neighbor] == 0 ) {
queue.push(neighbor);
}
}
}
// Prüfen auf Zyklus
if ( sorted.size() != indegree.size() ) {
throw runtime_error("Zyklus im Graph gefunden! Keine topologische Sortierung möglich.");
}
return sorted;
}
void
part1(const map<string, set<string>>& graph)
{
auto sorted = topologicalSort(graph);
cout << "Part 1: ";
ranges::copy(sorted, ostream_iterator<string>(cout));
cout << '\n';
}
void
part2(const map<string, set<string>>& graph, const int workers, const int base)
{
map<string, int> indegree;
// Eingangsgrade initialisieren
for ( const auto& [node, neighbors]: graph ) {
if ( !indegree.contains(node) ) {
indegree[node] = 0;
}
for ( const auto& neighbor: neighbors ) {
indegree[neighbor]++;
}
}
set<string> available;
for ( const auto& [node, deg]: indegree ) {
if ( deg == 0 ) {
available.insert(node);
}
}
set<pair<int, string>> finishing;
int active_workers = 0;
int time = 0;
while ( !indegree.empty() ) {
while ( !finishing.empty() && finishing.begin()->first == time ) {
auto [finish_time, node] = *finishing.begin();
finishing.erase(finishing.begin());
active_workers--;
indegree.erase(node);
if ( !graph.contains(node) ) {
continue;
}
for ( const auto& neighbor: graph.at(node) ) {
indegree[neighbor]--;
if ( indegree[neighbor] == 0 ) {
available.insert(neighbor);
}
}
}
while ( active_workers < workers && !available.empty() ) {
auto node = *available.begin();
available.erase(available.begin());
int duration = base + (node.at(0) - 'A' + 1);
int finish_time = time + duration;
finishing.emplace(finish_time, node);
active_workers++;
}
if ( finishing.empty() ) {
if ( available.empty() ) {
break;
}
else {
time++;
}
}
else {
time = finishing.begin()->first;
}
}
cout << "Part 2: " << time << '\n';
}
} // namespace
int
main()
{
auto graph = read_file("data/day07.txt");
try {
part1(graph);
static const int WORKERS = 5;
static const int BASE = 60;
part2(graph, WORKERS, BASE);
}
catch ( exception& e ) {
cerr << "Fehler: " << e.what() << '\n';
}
}
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