void Graph::strongly_connected_components()
{
	stack<int> finalization;
	Graph G_transpose;

	for (int i = 0; i < vertices_number; ++i)
	{
		if (colors[i] == 0)
			DFS_visit_SCC(i, finalization);
	}

	for (int i = 0; i < vertices_number; ++i)
		G_transpose.add_vertex();

	for (int i = 0; i < vertices_number; ++i)
		for (auto v : adj_lists[i])
			G_transpose.add_edge(v, i);

	while (!finalization.empty())
	{
		int v = finalization.top();
		finalization.pop();

		if (G_transpose.colors[v] == 0)
		{
			G_transpose.DFS_visit_SCC_transpose(v);
			cout << endl;
		}
	}
}

void Graph::DFS_visit_SCC(int vertex, stack<int>& finalization)
{
	colors[vertex] = 1;

	for (auto neighbour : adj_lists[vertex])
	{
		if (colors[neighbour] == 0)
		{
			DFS_visit_SCC(neighbour, finalization);
		}
	}

	finalization.push(vertex);
}

void Graph::DFS_visit_SCC_transpose(int vertex)
{
	cout << vertex << " ";
	colors[vertex] = 1;

	for (auto neighbour : adj_lists[vertex])
	{
		if (colors[neighbour] == 0)
		{
			DFS_visit_SCC_transpose(neighbour);
		}
	}
}