/**
* Unit tests the {@code BellmanFordSP} data type.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
In in = new In(args[0]);
int s = Integer.parseInt(args[1]);
EdgeWeightedDigraph G = new EdgeWeightedDigraph(in);
BellmanFordSP sp = new BellmanFordSP(G, s);
// print negative cycle
if (sp.hasNegativeCycle()) {
for (DirectedEdge e : sp.negativeCycle())
StdOut.println(e);
}
// print shortest paths
else {
for (int v = 0; v < G.V(); v++) {
if (sp.hasPathTo(v)) {
StdOut.printf("%d to %d (%5.2f) ", s, v, sp.distTo(v));
for (DirectedEdge e : sp.pathTo(v)) {
StdOut.print(e + " ");
}
StdOut.println();
}
else {
StdOut.printf("%d to %d no path\n", s, v);
}
}
}
}
/**
* Reads the currency exchange table from standard input and
* prints an arbitrage opportunity to standard output (if one exists).
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
// V currencies
int V = StdIn.readInt();
String[] name = new String[V];
// create complete network
EdgeWeightedDigraph G = new EdgeWeightedDigraph(V);
for (int v = 0; v < V; v++) {
name[v] = StdIn.readString();
for (int w = 0; w < V; w++) {
double rate = StdIn.readDouble();
DirectedEdge e = new DirectedEdge(v, w, -Math.log(rate));
G.addEdge(e);
}
}
// find negative cycle
BellmanFordSP spt = new BellmanFordSP(G, 0);
if (spt.hasNegativeCycle()) {
double stake = 1000.0;
for (DirectedEdge e : spt.negativeCycle()) {
StdOut.printf("%10.5f %s ", stake, name[e.from()]);
stake *= Math.exp(-e.weight());
StdOut.printf("= %10.5f %s\n", stake, name[e.to()]);
}
}
else {
StdOut.println("No arbitrage opportunity");
}
}
