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MathGroup Archive 2002

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Re: Irritating Little Problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg32958] Re: Irritating Little Problem
  • From: Richard Palmer <dickp at bellatlantic.net>
  • Date: Thu, 21 Feb 2002 02:07:16 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

> 
> In a message dated 2/19/02 3:25:04 AM, micweij at eka.ericsson.se writes:
> 
>> I have a simple vector
>> and I want to find the position of elements that are equal.
>> 
>> I.e I want to test the vector and find all cases of similar elements.
>> 
>> Brute force is not what I want, it can be a long vector.
>> 


If this is a really big industrial size problem, use hash tables.  You can
find a discussion of hash tables in any good computer science text.  If you
can read al the elements of the list into memory easily, then many of the
solutions given should work.

Richard Palmer



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