11 Jul
2007
11 Jul
'07
9:07 p.m.
2007/7/11, Larry Clapp <larry@theclapp.org>: > On Tue, Jul 10, 2007 at 10:35:45PM -0500, Ivan Salazar wrote: > > 2007/7/9, Ryan Davis <ryan@acceleration.net>: > > > How about the problem in today's XKCD?: http://xkcd.com/c287.html > > OK... This is the second time I've heard of the knapsack problem. > > I've searched a little and I have some questions: > > - Are repetitions allowed (one kind of appetizer chosen more than > > once)? > > Yes. > > > - Should we maximize or minimize the number of appetizers? > > Either. Whatever fits. > > > If I were the waiter, it wouldn't matter if I chose an appetizer > > more than once but I'd try to carry less appetizers. > > If I were the costumer, I'd like a diverse mix (no repetitions) and > > more appetizers. > > > > I'm thinking about programming a more general algorithm, something > > like this: > > > > (defun serve-appetizers (menu amount &key (:with-reps nil) (:minimize t)) > > ;... lots of code > > > > I have to do more research obviously (maybe it isn't feasible to > > program such thing, I don't now). > > It's feasible to *program* it. It's frequently not feasible to *run* > it. NP-complete problems grow in runtime very quickly. That is, you > can solve one in a minute for n=5, an hour for n=6, a day for n=7, and > a year for n=8 (pulling these numbers out of thin air just to > illustrate the point). > > I *think* that factoring numbers is NP-complete. Note that the > security of public-key cryptography hinges on the difficulty of > factoring large numbers. > > > Have you got any particular idea or solution? > > Use very small data sets. :) > > ... I've said all this on the assumption that because you're > unfamiliar with the knapsack problem, you're also unfamiliar with > NP-complete problems in general (like the travelling salesman > problem); if this is not true, I apologize. > > -- Larry > > _______________________________________________ > quiz mailing list > quiz@common-lisp.net > http://common-lisp.net/cgi-bin/mailman/listinfo/quiz > OK, was this quiz a joke then? u_u