Aggiunto graph

graph/DirectedGraph.java

@@ -0,0 +1,12 @@
+package graph;
+
+/**
+ * Created with MONSTER.
+ * User: xgiovio
+ * Date: 20/05/2014
+ * Time: 19:59
+ */
+public interface DirectedGraph<V, E> extends  Graph<V,E>{
+    public boolean isDirected(Edge<E> e);
+    public Edge<E> insertDirectedEdge(Vertex<V> u, Vertex<V> v, V o);
+}