use Bit::Vector;
use strict;
use warnings;

my $vector = Bit::Vector->new(1_000_000_000);
$vector->Fill();

my @ranges = ([39887, 399900],
              [23,    900],
              [8000,  10000],
              [50000, 1000500]);

$vector->Interval_Empty($_->[0] - 1, $_->[1] - 1) for @ranges;

my $start = 0;
while ($start < $vector->Size()
       and my ($min, $max) = $vector->Interval_Scan_inc($start))
{
    print(($min+1), "-", ($max+1), "\n");
    $start = $max + 2;
}