path: root/algos.c

#include "algos.h"

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);
	}
}

// Voir notice de convention ci-dessous
void max_clique_b(const graph g, set k, set c, set a, 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 {
		while (!(is_set_empty(a))) {
			int x = elt_of_set(a);
			set_remove_ip(x, a);

			set k2 = set_add(x, k);
			set c2 = set_inter(c, graph_neighbours(g, x));
			set a2 = set_inter(a,  graph_neighbours(g, x));
			
			max_clique_b(g,k2, c2, a2, mc);
			delete_set(k2);
			delete_set(c2);
			delete_set(a2);
		}
	}
}

// Convention : lors d'un appel de fonction, les set donnés en
// argument peuvent être modifiés à la guise de l'algorithme
// Il est donc de la responsabilité de l'appellant de vérifier qu'à
// chaque appel les sets sont utilisables et cohérents
void max_clique_c(const graph g, set k, set c, set a, set *mc) {
	if (set_size(k) + set_size(c) <= set_size(*mc)) return;

	if (is_set_empty(c)) {
		if (set_size(k) > set_size(*mc)) { // useless condition
			delete_set(*mc);
			*mc = copy_set(k);
			printf("Found new max clique: "); dump_set(*mc); fflush(stdout);
		}
	} else {
		set c_it = copy_set(c);
		int u = elt_of_set(c_it), n = 0;
		set_remove_ip(u, c_it);

		{	set temp = set_inter(c, graph_neighbours(g, u));
			n = set_size(temp);
			delete_set(temp);
		}

		int heur = u;
		while (!is_set_empty(c_it)) {
			int uprime = elt_of_set_heur(c_it, heur);
			heur = uprime;

			set_remove_ip(uprime, c_it);

			set temp = set_inter(c, graph_neighbours(g, uprime));
			if (set_size(temp) > n) {
				n = set_size(temp);
				u = uprime;
			}
			delete_set(temp);
		}
		delete_set(c_it);


		set t = set_diff(a, graph_neighbours(g, u));
		heur = u;
		while (!is_set_empty(t)) {
			int x = elt_of_set_heur(t, heur);
			heur = x;

			set k2 = set_add(x, k);
			set c2 = set_inter(c, graph_neighbours(g, x));
			set a2 = set_inter(a, graph_neighbours(g, x));
			max_clique_c(g, k2, c2, a2, mc);
			delete_set(a2);
			delete_set(c2);
			delete_set(k2);

			set_remove_ip(x, a);
			delete_set(t);
			t = set_diff(a, graph_neighbours(g, u));
		}
		delete_set(t);
	}
}