Re: Dictionary searching code

[Paul_Koning/US/3Com%3COM@smtp1.isd.3com.com]

At 08:02 PM 4/19/96 -0500, Adam wrote:
> Does anyone have some code that will search a dictionary, and
>tell me *quickly* if an arbitrary chunk of text is in the dictionary?
>Pre-indexing steps are fine, as is using big chunks of disk for hash
>tables.  The point of course, is to check arbitrary possible plaintext
>that a test decryption produces.

If you want to do string matching (search for an exact match on a string --
as opposed to checking whether a set of words is in a database) a good
choice would be the Boyer-Moore algorithm.  It has the nice property
that worst case it requires O(n) time (n = dictionary byte count) but
on average it is quite a lot better -- and furthermore, the longer the string
you're looking for, the faster it gets...

 paul

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