my $numArrays = keys %ids;
my %count = ();
my @intersection = ();
foreach my $k (keys %ids) {
    my %uniq = map { $_ => 1 } @{ $ids{$k} };
    $count[$_]++ for keys %uniq;
}
foreach my $v (keys %count) {
    push @intersection, $v if $count[$v] == $numArrays;
}