Re: [FWP] Closest hash value

["Edward M. Perry" <eperry@learjet.com>]

> "Edward M. Perry" <eperry@learjet.com> writes:
> 
> > Here is the problem: given a key ($key), and a hash (%h), I want the value
> > of the closest hash key. I came up with this which is only moderately fun.
> > Really it works pretty well, assuming keys are numeric and the hash is
> > small. Mapping to %temp is weak.  
> > 
> > An array seems unreasonable because in reality the keys (or indicies) are
> > large and the array would be very sparse.
> >[hashing example snipped]
> 
> It sounds like you want (gasp!) a data structure that isn't an array
> or a hash.  A binary tree would be a good choice.  If linear-time is
> acceptable, or if the keys arrive in reasonably "random" order, then
> it's definitely good enough; otherwise you may want to rotate it.
> 
> How many items have you got?
> 
> -- 
> Ariel Scolnicov        |"GCAAGAATTGAACTGTAG"            |ariels@compugen.co.il
> Compugen Ltd.          |Tel: +972-2-6795059 (Jerusalem)	\  NEW IMPROVED URL!
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> Tel-Aviv 69512, ISRAEL |Fax: +972-3-7658555  http://3w.compugen.co.il/~ariels

The real problem is pretty small, about 100 keys, 20 lookups, and speed is
not really a concern. A B-Tree would be overkill for this problem, but
probably would be a good solution for a larger data set. Your suggestion
did get me thinking about good ways to binary search a set of hash keys
though...Gotta go do it. Thanks.

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