[Haskell-cafe] Norvig's Sudoku Solver in Haskell
emmanuel.delaborde at citycampus.com
Sun Aug 26 17:17:38 EDT 2007
> From: Malte Milatz <malte at gmx-topmail.de>
> Subject: Re: [Haskell-cafe] Norvig's Sudoku Solver in Haskell
> Your program was wrapped by your mail client, so you may want to
> your program for easier digestion.
here it is : http://hpaste.org/2452
> Your profiling output suggests that much time is consumed by the
> function. Since you're using (fromJust . lookup) everywhere anyway, a
> data structure not envolving the Maybe type is probably a more succint
> choice. And why bother with characters and strings?
no rationale except that's what the original Python script did use
>> newV2 <- case length newCell of
>> 0 -> Nothing
>> 1 -> do let peersOfS = [ s' | s' <- lookup s peers ]
>> res <- foldM eliminate newV (zip peersOfS
>> (cycle newCell))
>> return res
>> _ -> return newV
> The use of “length” here is not an actual performance problem, but
> unnecessary. Simply write: case newCell of  -> ...
> [_] -> ...
> _ -> ...
> The same is valid for your other use of length.
I see, thanks !
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