if (stats->expanded_pairs == 0) {
XBT_INFO("Expanded states = %lu", stats->expanded_states);
XBT_INFO("Visited states = %lu", stats->visited_states);
if (stats->expanded_pairs == 0) {
XBT_INFO("Expanded states = %lu", stats->expanded_states);
XBT_INFO("Visited states = %lu", stats->visited_states);