public void Initialize()
{
_graph = new DirectedWeightedGraph <string>();
var verticesSet1 = new string[] { "a", "z", "s", "x", "d", "c", "f", "v" };
_graph.AddVertices(verticesSet1);
_graph.AddEdge("a", "s", 1);
_graph.AddEdge("a", "z", 2);
_graph.AddEdge("s", "x", 3);
_graph.AddEdge("x", "d", 1);
_graph.AddEdge("x", "c", 2);
_graph.AddEdge("x", "a", 3);
_graph.AddEdge("d", "f", 1);
_graph.AddEdge("d", "c", 2);
_graph.AddEdge("d", "s", 3);
_graph.AddEdge("c", "f", 1);
_graph.AddEdge("c", "v", 2);
_graph.AddEdge("c", "d", 3);
_graph.AddEdge("v", "f", 1);
_graph.AddEdge("f", "c", 2);
}