sub missingNumbers {
    my $arr = shift;
    my $brr = shift;
    
    my (%h1, %h2);
    my @res;

    grep { $h1{$_} += 1; } @$arr;
    grep { $h2{$_} += 1; } @$brr;

    foreach my $e (keys %h2) {
        if (!exists($h1{$e})) {
            push(@res, $e);
        } elsif (exists($h1{$e}) && $h1{$e} != $h2{$e}) {
            push(@res, $e);
        }
    }

    return sort {$a <=> $b} @res;
}