use Set::Bag;

my @a = ( 1, 2, 3 );
my @b = ( 2, 3, 1 );
my @c = ( 1, 2, 4 );

print "(@a) and (@b) are equal sets.\n" if identical( \@a, \@b );
print "(@a) and (@c) are equal sets.\n" if identical( \@a, \@c );
print "(@b) and (@c) are equal sets.\n" if identical( \@b, \@c );

sub identical {
    my ( $left, $right ) = @_;
    return 0 if scalar @$left != scalar @$right;
    my $bag_a = Set::Bag->new;
    my $bag_b = Set::Bag->new;
    $bag_a->over_delete(1);
    $bag_b->over_delete(1);
    $bag_a->insert( $_ => 1 ) for @$left;
    $bag_b->insert( $_ => 1 ) for @$right;
    return 1 if    $bag_a->difference($bag_b) eq '()' 
                && $bag_b->difference($bag_a) eq '()';
    return 0;
}