TopologicalSort

void _recursive_topological(int from)
{
	visited_topo[from] = true;

	//go through neighbors
	for(auto element: graph[from])
	{
		if(!visited_topo[element.vertex_number])
		{
			visited_topo[element.vertex_number] = true;
			_recursive_topological(element.vertex_number);
		}
	}


	ordered_nodes.push_back(from);


}

void topological_sort()
{
	for(int i=0; i < graph.size();i++)
	{
		if(!visited_topo[i])
			_recursive_topological(i);
	}

	ordered_nodes.reverse();

	for(auto element : ordered_nodes)
	{
		std::cout << element << " ";
	}

	std::cout << std::endl;

}