int DigraphTransitiveClosure (PtDigraph pdig)
{

    if (pdig == NULL)
        return NO_DIGRAPH;

    if (!pdig->NVertexes)
        return DIGRAPH_EMPTY;

    if((pvertlist = (unsigned int*) malloc(pdig->NVertexes * sizeof(unsigned int))) == NULL)
        return NO_MEM;

    if ((pvertcost = (int *) malloc (pdig->NVertexes * sizeof(int))) == NULL)
        return NO_MEM;

    if ((pvertpred = (unsigned int *) malloc (pdig->NVertexes * sizeof(unsigned int))) == NULL)
        return NO_MEM;

    PtBiNode node;
    unsigned int I, *pvertlist, *pvertpred, *pvertcost;

    for(node = pdig->Head; node != NULL; node = node->PtNext) {
        Reach (pdig, node->Number, pvertlist);
        DijkstraPQueue(pdig, node->Number, pvertpred, pvertcost);
        if((pvertlist[0] != 0){         /* se houver vertices alcancaveis por pv */
            for(I = 1; I < pvertlist[0]; I++) {
                if(!InPosition(node->Number, pvertlist[I]) {                /* se a aresta para I+1 nao existir */
                    InEdge(pdig, node->Number, pvertlist[I], pvertcost[I]); /* insere aresta de number para I */
                }
            }
        }
    }

    free(pvertlist);
    free(pvertcost);
    free(pvertpred);

    pvertlist = NULL; /* o adrego fala disto no livro, programaçao defensiva xD */
    pvertcost = NULL;
    pvertpred = NULL;

    return OK;
}