Пример #1
0
    private DirectedEdge[] edgeTo;    // edgeTo[v] = last edge on longest s->v path

    /**
     * Computes a longest paths tree from {@code s} to every other vertex in
     * the directed acyclic graph {@code G}.
     * @param G the acyclic digraph
     * @param s the source vertex
     * @throws IllegalArgumentException if the digraph is not acyclic
     * @throws IllegalArgumentException unless {@code 0 <= s < V}
     */
    public AcyclicLP(EdgeWeightedDigraph G, int s) {
        distTo = new double[G.V()];
        edgeTo = new DirectedEdge[G.V()];

        validateVertex(s);

            for (int v = 0; v < G.V(); v++)
                distTo[v] = double.NegativeInfinity;// NEGATIVE_INFINITY;
        distTo[s] = 0.0;

        // relax vertices in topological order
        Topological topological = new Topological(G);
        if (!topological.hasOrder())
            throw new ArgumentException("Digraph is not acyclic.");
        foreach (int v in topological.order()) {
                foreach ( DirectedEdge e in G.adj(v))
                relax(e);
        }
    }
Пример #2
0
    private DirectedEdge[] edgeTo;   // edgeTo[v] = last edge on shortest s->v path


    /**
     * Computes a shortest paths tree from {@code s} to every other vertex in
     * the directed acyclic graph {@code G}.
     * @param G the acyclic digraph
     * @param s the source vertex
     * @throws IllegalArgumentException if the digraph is not acyclic
     * @throws IllegalArgumentException unless {@code 0 <= s < V}
     */
    public AcyclicSP(EdgeWeightedDigraph G, int s) {
        distTo = new double[G.V()];
        edgeTo = new DirectedEdge[G.V()];

        validateVertex(s);

        for (int v = 0; v < G.V(); v++)
            distTo[v] = Double.POSITIVE_INFINITY;
        distTo[s] = 0.0;

        // visit vertices in topological order
        Topological topological = new Topological(G);
        if (!topological.hasOrder())
            throw new IllegalArgumentException("Digraph is not acyclic.");
        for (int v : topological.order()) {
            for (DirectedEdge e : G.adj(v))
                relax(e);
        }
    }