private void relax(EdgeWeightDigraph G, int v) throws Exception {
for (DirectedEdge e : G.adj(v)) {
int w = e.to();
if (distTo[w] > distTo[v] + e.weight()) {
distTo[w] = distTo[v] + e.weight();
edgeTo[w] = e;
if (pq.contains(w)) {
pq.changeKey(w, distTo[w]);
} else {
pq.increaseKey(w, distTo[w]);
}
}
}
}
public DijkstraSP(EdgeWeightDigraph G, int s) throws Exception {
edgeTo = new DirectedEdge[G.V()];
distTo = new double[G.V()];
pq = new IndexMinPQ<Double>(G.V());
for (int v = 0; v < G.V(); v++) {
distTo[v] = Double.POSITIVE_INFINITY;
}
distTo[s] = 0.0;
pq.insert(s, 0.0);
while (!pq.isEmpty()) {
relax(G, pq.delMin());
}
}