spx2,
Would you mind coding up a complete example? I ask because I haven't used Bit::Vector that much and don't immediately see how it could be used to accomplish this task. I solved this problem a long time ago but am always interested in seeing how abstraction modules can make my life easier.

Keep in mind that the goal would be to have a known set ( say 'A' .. 'Z') and a known subset size (say 5). Then, given a valid subset of the specified size (say AMTXZ), determine if that subset has been "seen" before. If not, perform some action and then mark it as being "seen". Here is some starter code to give you an idea of what I have already accomplished: 

my @set = 'A' .. 'Z';
my $subset_size = 5;
my @subset = qw/A M T X Z/;

process_subset(@subset);
process_subset(@subset);

sub process_subset {
    if (seen(@_)) {
        print "Already processed '@_'\n";
        return;
    }
    print "Performing expensive operation on '@_'\n";
    set_seen(@_);
}

sub seen {
    # For you to implement
    # ...
}

sub set_seen {
    # For you to implement
    # ...
}

[download]

Keep in mind that @set, @subset_size and @subset are all subject to change - so it has to be a general purpose solution.

Cheers - L~R

In reply to Re^2: Algorithm to convert combinations to bitstring by Limbic~Region
in thread Algorithm to convert combinations to bitstring by Limbic~Region

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.