Programming challenge: wildcard exclusion in cartesian products

Dr.Ruud rvtol+news at isolution.nl
Thu Mar 23 14:14:17 CET 2006


wkehowski at cox.net schreef:

> The solution that would have the most utility would be one where the
> elements are generated one-by-one, loop-like, so that they can be used
> in the body of a loop, and to avoid the fact that even with exclusion
> the cardinality of the target set EX^n could be in the millions even
> with a full list of wc's, that is, a list containing at least one wc
> of every length in 2..(n-1). I don't know enough Lisp, Haskell or
> Qi/Prolog to know if the solutions so far can be modified to do this.
> The Python program is too slow for large sets.

Use a bitmapping, see also
  news:dvlqqi$2764$1 at agate.berkeley.edu

Detect the exclusions with a bitwise AND.

-- 
Affijn, Ruud

"Gewoon is een tijger."
echo 014C8A26C5DB87DBE85A93DBF |perl -pe 'tr/0-9A-F/JunkshoP cartel,/'




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