Sounds like set arithmetic to me.. I would recommend Set::Scalar

I threw this together as an example. Course order is wacked when you use sets...

use strict;
use Set::Scalar;

my $a = [1,2,3,4,5,6];
my $b = [3,4,5,7,8];
my $c = [3,6,8,9];
my $sa = Set::Scalar->new(@$a);
my $sb = Set::Scalar->new(@$b);
my $sc = Set::Scalar->new(@$c);


my $x = 3;

my $mina = $sa - $sb - $sc + ($sa * $x);
my $minb = $sb - $sa + ($sb * $x);
my $minc = $sc - $sb + ($sc * $x);

print("Minimum Set A:" . join(',', $mina->members) . "\n");
print("Minimum Set B:" . join(',', $minb->members) . "\n");
print("Minimum Set C:" . join(',', $minc->members) . "\n");

__END__

Minimum Set A:1,3,2
Minimum Set B:8,3,7
Minimum Set C:6,3,9
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