Exemple #1
0
unsigned int graph_connected_components(graph_t g) {
    unsigned int classes_count = 0, n, m, left, right;
    union_find_t uf;
    edge_t *edges;

    n = graph_vertices_count(g);
    m = graph_edges_count(g);
    uf = union_find_create(n);

    edges = graph_edges(g);
    for (unsigned int i = 0; i < m; i++) {
        left = vertex_label(edge_left_vertex(edges[i]));
        right = vertex_label(edge_right_vertex(edges[i]));
        left = union_find_find(uf, left);
        right = union_find_find(uf, right);
        if (!union_find_connected(uf, left, right)) {
            union_find_union(uf, left, right);
        }
        edges[i] = edge_destroy(edges[i]);
    }
    free(edges);
    classes_count = union_find_count(uf);
    uf = union_find_destroy(uf);

    return (classes_count);
}
Exemple #2
0
graph_t kruskal(graph_t graph) {
    graph_t result = graph_empty(graph_vertices_count(graph));
    unsigned int L, R, num_edges = graph_edges_count(graph);
    vertex_t l = NULL, r = NULL;
    pqueue_t Q = pqueue_empty(num_edges);
    union_find_t C = union_find_create(graph_vertices_count(graph));
    edge_t E = NULL, *edges = graph_edges(graph);
    for (unsigned int i = 0; i < num_edges; i++) {
        pqueue_enqueue(Q, edges[i]);
    }

    free(edges);
    edges = NULL;

    while (!pqueue_is_empty(Q) && union_find_count(C) > 1) {
        E = edge_copy(pqueue_fst(Q));
        l = edge_left_vertex(E);
        r = edge_right_vertex(E);
        L = union_find_find(C, vertex_label(l));
        R = union_find_find(C, vertex_label(r));

        if (L != R) {
            union_find_union(C, L, R);
            E = edge_set_primary(E, true);
        } else {
            E = edge_set_primary(E, false);
        }
        result = graph_add_edge(result, E);
        pqueue_dequeue(Q);
    }

    while (!pqueue_is_empty(Q)) {
        E = edge_copy(pqueue_fst(Q));
        pqueue_dequeue(Q);
        E = edge_set_primary(E, false);
        result = graph_add_edge(result, E);
    }

    Q = pqueue_destroy(Q);
    C = union_find_destroy(C);

    return result;
}
Exemple #3
0
graph_t kruskal(graph_t graph) {
/* Computes a MST of the given graph.
 *
 * This function returns a copy of the input graph in which
 * only the edges of the MST are marked as primary. The
 * remaining edges are marked as secondary. 
 *
 * The input graph does not change. 
 * 
*/
    graph_t mst;
    union_find_t uf;
    pqueue_t pq;
    edge_t *edges;
    edge_t e;
    unsigned int left, right, n, m;

    /* Inicialización */
    n = graph_vertices_count(graph);
    m = graph_edges_count(graph);
    mst = graph_empty(n);
    uf = union_find_create(n);
    pq = pqueue_empty(m);

    /* Llenar `pq` */
    edges = graph_edges(graph);
    for (unsigned int j = 0; j < m; j++) {
        pqueue_enqueue(pq, edges[j]);
    }
    /* Ahora las aristas están en `pq` */
    free(edges);
    edges = NULL;


    /* Principal */
    while (!pqueue_is_empty(pq) && union_find_count(uf) > 1) {
        e = edge_copy(pqueue_fst(pq));
        left = vertex_label(edge_left_vertex(e));
        right = vertex_label(edge_right_vertex(e));
        left = union_find_find(uf, left);
        right = union_find_find(uf, right);
        if (!union_find_connected(uf, left, right)) {
            e = edge_set_primary(e, true);
            union_find_union(uf, left, right);
        } else {
            e = edge_set_primary(e, false);
        }
        mst = graph_add_edge(mst, e);
        pqueue_dequeue(pq);
    }

    /* Agregar aristas restantes como secundarias */
    while (!pqueue_is_empty(pq)) {
        e = edge_copy(pqueue_fst(pq));
        e = edge_set_primary(e, false);
        mst = graph_add_edge(mst, e);
        pqueue_dequeue(pq);
    }

    /* Destroy */
    uf = union_find_destroy(uf);
    pq = pqueue_destroy(pq);

    return (mst);
}