@range = sort { $a->[0] <=> $b->[0] } @range;
for (my $i = 0; $i < @range; $i++) {
CURRENT:
    {
        my $e = $range[$i][1];
        for(my $j = $i+1; $j < @range; $j++) {
            unless($range[$j][0] > $e) {
                $range[$i][1] = $range[$j][1] if ($range[$j][1] > $e);
                splice @range, $j, 1;
                redo CURRENT;
            }
        }
    }
}