public void printPath() {
for (Vertex v : vs) {
printPath(v);
System.out.println();
}
System.out.println();
}
private void printPath(Vertex v) {
if (v == vs[start]) System.out.print(v + " ");
else {
if (v.pred == null) System.out.print("no path from " + vs[start] + " to " + v);
else {
printPath(v.pred);
System.out.print(v + " ");
}
}
}