v = _vertices + without_predecessors[l];
v->distance_from_source = rank;
for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {
v = _vertices + without_predecessors[l];
v->distance_from_source = rank;
for(e = v->leaving_edge_list_root; e; e = e->next_leaving_edge) {