in reply to Re^2: unordered sets of N elements
in thread unordered sets of N elements

If you want to solve it recursively, the induction is good. However, I'd use L~R's googled formula with my mod for different number of sides.

Note - none of the formulas help if you have 2d6+2d8 with the same constraint across all four dice.

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Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

I shouldn't have to say this, but any code, unless otherwise stated, is untested

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Re^4: unordered sets of N elements
by Limbic~Region (Chancellor) on Jul 13, 2004 at 14:39 UTC
    dragonchild,
    That may be where using one of those nifty CPAN modules and sorting/joining/hashing comes into play. 
    #!/usr/bin/perl
use strict;
use warnings;
use Algorithm::Loops 'NestedLoops';

my (@combo, %seen);
my %roll = (
    'type1' => { 'sides' => 6, 'count' => 2 },
    'type2' => { 'sides' => 8, 'count' => 2 },
);
my $die = 4;

my $iter = NestedLoops(
    [ map { ( [1..$_->{sides}] ) x $_->{count} } values %roll ],
    { OnlyWhen => \&ok }
);
print "@combo\n" while ( @combo = $iter->() );

sub ok {
    my $key = join '' , sort @_;
    return undef if exists $seen{$key} || length $key != $die;
    $seen{$key} = undef;
    return 1;
}

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    Cheers - L~R

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