public void Init()
 {
     _graphBuilder = new HwDirectedGraphBuilder2("directed_graph_02.txt");
     _graph = _graphBuilder.Build();
     _dfs = new Dfs(_graph);
 }
 public void Init()
 {
     _graphBuilder = new UndirectedGraphBuilder("undirected_graph_lecture_03.txt");
     _graph = _graphBuilder.Build();
     _dfs = new Dfs(_graph);
 }