Author: blass uri
Date: 02:52:09 06/25/00
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On June 25, 2000 at 05:14:10, Andrew Dados wrote: >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] I understand that I can do for (i=0;i<99999;i++) hash[i]=hash[i+1] by treating hash as a pointer but the problem is what to do if I want to do for (i=30000;i<90000;i++) hash[i]=hash[i+1] without changing hash[i] for i<30000. The reason that I want to do is that hash is an array of numbers in increasing order and I want to do hash[30000]=newnumber in order to keep the right order of numbers because I need the right order to help me to search if a new number is equal to one of the numbers in the hash table. I guess that there is a simple way to do it in C and this is what I ask for. I also ask for a simple way to translate a sequence of integer numbers to one integer when different sequences usually get different numbers. Uri
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