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  1. #1
    Join Date
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    need algorithm name

    hello all.. been a few days since i visited "the forums"

    need some help.

    what i would like to do:

    -consider an excel sheet. dealing with 5 columns.
    -each column has a heading, followed by a bunch of numerical entries
    -in the first column i can have 10 possible values, second, 20 possible values, 3rd 5 possible values, 4th 3, and 5th 2 poss values.
    -want to write a program to generate all possible combinations of values.

    question:
    is there a well known algorithm to do this? if so, what is it called? if not, suggestions please.

    please do not worry about hooking into excel from c++ etc yet. I have not decided yet whether i will use vba or c++. i'm just looking for an algorithm to do this. also, keep in mind that there is a large number of combinations (which will only get larger in the future- never smaller). there are many other things i have to take into account, so i'm not in the coding phase yet. i just want to see what i can get by way of algorithms so i can plan the rest of the stuff!

    i seem to remember from univ courses some sort of good algorithm to do this, but i can't remember! its been a logn time!

    thanks!

    ps- as much as this sounds like a school assignment, it is not!!!!!!!!!!! i have been done school for a few years!
    Last edited by drewdaman; August 19th, 2005 at 03:04 PM.

  2. #2
    GCDEF is offline Elite Member Power Poster
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    Re: need algorithm name

    Don't know if there's a specific algorithm, but it isn't difficult. Just use a series of nested loops.

    The outer loop would loop through the values of the first column, with successive inner loops interating the other columns.

  3. #3
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    Re: need algorithm name

    thanks for the reply GCDEF.

    yes that is true. but i was wondering what the most efficient way to do it is. i might have to do it many times and i might be dealing with a very large number of combinations.

    another key thing to note is that this is not a simple truth table. The problem is that the number of possible values for each column are different. so in a normal truth table, you just have 0,1 as the possible entries for each row. here, i might have ten possible values for the entries under column 1, 20 possible values for the entries under col 2 and so on.. i guess your idea of nested loops would work, but i would need five-maybe even more- (and we thought bubble sort was bad )

  4. #4
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    Re: need algorithm name

    10, 20, 5, 3, 2... This doesn't look to me like a the result of a simple formula (combinations, arithmetic/geomethric series, etc.)
    Marius Bancila
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  5. #5
    GCDEF is offline Elite Member Power Poster
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    Re: need algorithm name

    Quote Originally Posted by drewdaman
    thanks for the reply GCDEF.

    yes that is true. but i was wondering what the most efficient way to do it is. i might have to do it many times and i might be dealing with a very large number of combinations.

    another key thing to note is that this is not a simple truth table. The problem is that the number of possible values for each column are different. so in a normal truth table, you just have 0,1 as the possible entries for each row. here, i might have ten possible values for the entries under column 1, 20 possible values for the entries under col 2 and so on.. i guess your idea of nested loops would work, but i would need five-maybe even more- (and we thought bubble sort was bad )
    Some problems don't have an effecient solution. I believe this is one of them.

  6. #6
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    Re: need algorithm name

    Quote Originally Posted by cilu
    10, 20, 5, 3, 2... This doesn't look to me like a the result of a simple formula (combinations, arithmetic/geomethric series, etc.)
    nope.. making a small excel app (have decided now) for some cost, revenue type analysis.

    [quote= GCDEF]

    Some problems don't have an effecient solution. I believe this is one of them.
    [quote]

    i guess you're right... i will just do it that way then.

    thanks for the replies guys.

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