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/*
Projet d'algorithmique et programmation 2013-2014
(cours de C.Matthieu et J.Stern)
Alex AUVOLAT, Mendes OULAMARA
Sujet : Algorithme de Bron-Kerbosch pour Maximum-Clique
(cf maxclique.pdf)
*/
#include <stdlib.h>
#include "sets.h"
#include "graph.h"
/*
max_clique calculates the maximum clique in a graph. Arguments :
- g : the graph where the clique is looked for
- k : the clique we are currently examining
- c : the graph nodes we can potentially add to the clique
- mc : a pointer to the set containing the maximum clique found until now
Returns nothing (result is in *mc).
*/
void max_clique_a(const graph g, set k, set c, set *mc) {
if (is_set_empty(c)) {
if (set_size(k) > set_size(*mc)) {
delete_set(*mc);
*mc = copy_set(k);
printf("Found new max clique: "); dump_set(*mc); fflush(stdout);
}
} else {
set cc = copy_set(c);
while (!(is_set_empty(cc))) {
int x = elt_of_set(cc);
set_remove_ip(x, cc);
set k2 = set_add(x, k);
set c2 = set_inter(c, graph_neighbours(g, x));
max_clique_a(g,k2, c2, mc);
delete_set(k2);
delete_set(c2);
}
delete_set(cc);
}
}
// Driver
void usage(char *pname) {
printf("\nUsage:\n\t%s [options] [<graph file>]\n\n", pname);
printf("Available options:\n");
printf("\n -d\n\tRead input in DIMACS format\n");
printf("\n -o <file.dot>\n\tDump graph in graphwiz .dot format\n");
printf("\n -h, --help\n\tShow this help page\n");
exit(1);
}
int main(int argc, char **argv) {
int i;
int dimacs = 0;
char *filename = "-";
char *dump = NULL;
for (i = 1; i < argc; i++) {
if (!strcmp(argv[i], "-d")) {
dimacs = 1;
} else if (!strcmp(argv[i], "-o")) {
if (++i == argc) usage(argv[0]);
dump = argv[i];
} else if (argv[i][0] == '-') {
usage(argv[0]);
} else {
filename = argv[i];
}
}
FILE *f = stdin;
if (strcmp(filename, "-")) {
f = fopen(filename, "r");
if (f == NULL) {
fprintf(stderr, "Error: could not open file %s\n", filename);
return 1;
}
}
graph g = (dimacs ? load_graph_dimacs(f) : load_graph(f));
if (g == NULL) {
fprintf(stderr, "Error loading file %s\n", filename);
return 1;
}
fclose(f);
if (dump != NULL) {
f = fopen(dump, "w");
if (f == NULL) {
fprintf(stderr, "Error: could not open file %s for writing\n", dump);
return 1;
}
dump_graphviz(g, f);
fclose(f);
}
// do stuff with graph
set max_clique = empty_set(g->N);
set init_s = full_set(g->N);
set init_k = empty_set(g->N);
max_clique_a(g, init_k, init_s, &max_clique);
printf("Max clique: "); dump_set(max_clique);
delete_graph(g);
return 0;
}
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