sub partition {
    my @numbers - sort{ $b <=> $a } @_;
    my $adjust = 0;
    if( $numbers[ -1 ] < 0 ) {
        $adjust = - $number[ -1 ];
        $_ += $adjust for @numbers;
    }
     
    ...

    $_ -= $adjust for @part_1, @part_2;
    return \@part_1, \@part_2;
}