private int[] rank; // rank[v] = rank of vertex v in order
/**
* Determines whether the digraph {@code G} has a topological order and, if so,
* finds such a topological order.
* @param G the digraph
*/
public Topological(Digraph G) {
DirectedCycle finder = new DirectedCycle(G);
if (!finder.hasCycle()) {
DepthFirstOrder dfs = new DepthFirstOrder(G);
order = dfs.reversePost();
rank = new int[G.V()];
int i = 0;
for (int v : order)
rank[v] = i++;
}
}
/**
* Unit tests the {@code DirectedCycle} data type.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
In in = new In(args[0]);
Digraph G = new Digraph(in);
DirectedCycle finder = new DirectedCycle(G);
if (finder.hasCycle()) {
StdOut.print("Directed cycle: ");
for (int v : finder.cycle()) {
StdOut.print(v + " ");
}
StdOut.println();
}
else {
StdOut.println("No directed cycle");
}
StdOut.println();
}
