JAVA code

Create a new class called BetterDiGraph that implements the EditableDiGraph interface See the interface below for details.

EditableDigraph below:

import java.util.NoSuchElementException;

/** * Implements an editable graph with sparse vertex support. * * */ public interface EditableDiGraph { /** * Adds an edge between two vertices, v and w. If vertices do not exist, * adds them first. * * @param v source vertex * @param w destination vertex */ void addEdge(int v, int w);

/** * Adds a vertex to the graph. Does not allow duplicate vertices. * * @param v vertex number */ void addVertex(int v);

/** * Returns the direct successors of a vertex v. * * @param v vertex * @return successors of v */ Iterable getAdj(int v); /** * Number of edges. * * @return edge count */ int getEdgeCount(); /** * Returns the in-degree of a vertex. * @param v vertex * @return in-degree. * @throws NoSuchElementException exception thrown if vertex does not exist. */ int getIndegree(int v) throws NoSuchElementException; /** * Returns number of vertices. * @return vertex count */ int getVertexCount(); /** * Removes edge from graph. If vertices do not exist, does not remove edge. * * @param v source vertex * @param w destination vertex */ void removeEdge(int v, int w);

/** * Removes vertex from graph. If vertex does not exist, does not try to * remove it. * * @param v vertex */ void removeVertex(int v);

/** * Returns iterable object containing all vertices in graph. * * @return iterable object of vertices */ Iterable vertices();

/** * Returns true if the graph contains at least one vertex. * * @return boolean */ boolean isEmpty(); /** * Returns true if the graph contains a specific vertex. * * @param v vertex * @return boolean */ boolean containsVertex(int v); }