>explodes exponentially Nit pick: it explodes factorially, which is worse than exponential. The superset of a set of N elts is N!. (If order is meaningful (unl

>explodes exponentially Nit pick: it explodes factorially, which is worse than exponential. The superset of a set of N elts is N!. (If order is meaningful (unlikely here), it's slightly worse, which is all permutations of each member of the superset. But that's only ~exponential and is quickly swallowed by the factorial).