private Digraph initDG()
{
Digraph g = new Digraph(13);
g.addEdge(2, 3);
g.addEdge(0, 6);
g.addEdge(0, 1);
g.addEdge(2, 0);
g.addEdge(11, 12);
g.addEdge(9, 12);
g.addEdge(9, 10);
g.addEdge(9, 11);
g.addEdge(3, 5);
g.addEdge(8, 7);
g.addEdge(5, 4);
g.addEdge(0, 5);
g.addEdge(6, 4);
g.addEdge(6, 9);
g.addEdge(7, 6);
return(g);
}
public DirectedDFS(Digraph G, int s)
{
mark = new bool[G.v()];
dfs(G, s);
}