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Subject: Re: hash tables question

Author: Andrew Dados

Date: 02:14:10 06/25/00

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On June 25, 2000 at 03:27:07, blass uri wrote:

>Can somebody post a C program that translates arrays to 32 bits integers when
>usually different arrays get different numbers and also translates it in a way
>that it is easy to find if the 32 bits integer is new?
>
>I think that this is the idea behind hash tables
>
>I need it for my program that I use to solve equations and inequalities.
>
>I have an array possolution[256][100000] and
>I need to check if the possolution[256][i] is not identical to
>possolution[256][j]
>for all j<i(I do i++ only if it is not identical).
>
>If I can calculate the hash entry of possolution[256][i] and discover in a short
>time that the hash entry of possolution[256][i] is different than the hash entry
>of possolution[256][j] for j<i it will save my program a lot of time
>
>I need to know also how to do it in C with O(log[i]) steps and not in O(i) steps
>and I know only how to do it theoretically in O(log[i]) steps but I do not know
>how to do it in C because I do not know how to push an array forward(if I have
>an array hash[100000] I do not know how to do for (i=35000;i<90000;i++)
>hash[i]=hash[i+1] in a short time)

if you treat hash as a pointer to array, just decrement its start point by
SizeOf(hashentry), then remember then it has moved, so you don't access hash[i],
but rather hash[i+offset]
>
>Uri



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