Digraph.java with dfs circel detection output

strict digraph {

16[color=red];

17[color=red];

15[color=red];

16->17;

0->1;

0->2;

17->15;

1->2;

1->3;

2->3;

2->4;

19->19;

3->4;

3->5;

4->5;

4->6;

5->6;

5->7;

6->7;

6->8;

7->5;

15->16;

}

number of points: 13

number of edges: 19

hasCircle = true