2018/Day7/Day7A.cpp

68 lines
1.4 KiB
C++

#include <iostream>
#include <vector>
#include <fstream>
#include <unordered_map>
#include <set>
#include <tuple>
typedef std::unordered_multimap<char, char> graph_type;
std::tuple<graph_type, std::set<char>> build_graph()
{
graph_type graph;
std::ifstream file("Day7.in");
std::string line;
std::set<char> nodes;
while (std::getline(file, line)) {
char a = line[5];
char b = line[36];
std::cout << "a: " << a << ", b:" << b << std::endl;
graph.insert({ b, a });
nodes.insert(a);
nodes.insert(b);
}
return std::make_tuple(graph, nodes);
}
bool node_blocked(graph_type &graph, std::set<char> &to_consider, char node)
{
auto [start, end] = graph.equal_range(node);
for (auto pair = start; pair != end; ++pair) {
char parent = pair->second;
if (to_consider.count(parent) > 0) {
return true;
}
}
return false;
}
int main(int argc, char **argv)
{
auto [graph, to_consider] = build_graph();
std::vector<char> order;
while (!to_consider.empty()) {
for (auto node = to_consider.begin(); node != to_consider.end(); ++node) {
bool blocked = node_blocked(graph, to_consider, *node);
if (blocked)
continue;
order.push_back(*node);
std::cout << *node;
to_consider.erase(node);
break;
}
}
std::cout << std::endl;
return 0;
}