From: "Branimir Maksimovic" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
CC: Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Substring replacements
Date: Thu, 15 Dec 2005 00:55:02 +0000
From: Daniel Fischer <[EMAIL PROTECTED]>
To: "Branimir Maksimovic" <[EMAIL PROTECTED]>
CC: Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Substring replacements
Date: Wed, 14 Dec 2005 20:40:06 +0100
Hi Bane,
nice algorithm. Since comparing chars _is_ cheap, it is to be expected
that
all the hash-rotating is far more costly for short search patterns. The
longer the pattern, the better this gets, I think -- though nowhere near
KMP
(or would it?).
Yes,KMP is superior in single pattern search. We didn't tried Boyer-Moore
algorithm yet, though. But I think it would be
difficult to implement it in Haskell efficiently as it searches backwards
and jumps around, and we want memory savings.
Though, I even didn't tried yet, but it is certainly very interesting.
Forget what I've said.
Boyer-Moore *can* be implemented efficiently, it is similar to KMP it goes
forward, but when it finds last character in pattern, than starts to search
backwards.
This can be implemented easilly as Haskell lists naturaly reverse order
when putting from one list to other.
Heh, never say never :)
As I see from documents Boyer-Moore has best performance on average
and should be better than KMP.
Greetings,Bane.
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