1..10 - interval
 and 

2..5 - subinterval
4..7 - subinterval 


##</code><code>##

1->0
2->1
3->1
4->2
5->2
6->1
7->1
8->0
9->0
10->0

##</code><code>##


#!/usr/bin/perl

use Bit::Vector;
use Data::Dumper;
use strict;



my @vecArray;
my $x=0;
while($x<4){
	$vecArray[$x] =  Bit::Vector->new(21);
	my $int = int(rand(21));
	my $min = $int;
	my $max = $int<=20-5 ? $int+5 : $int; 
	$vecArray[$x]->Interval_Fill($min,$max);
	$x++;
}
my $set1=  Bit::Vector->new(21);
$set1->Intersection($vecArray[0],$vecArray[2]);
my $start = 0;

while ($start < $set1->Size() and my ($min, $max) = $set1->Interval_Scan_inc($start)){
    print $min . "-" . $max . "\n";
    $start = $max+1 ;
}


##</code><code>##


|interval| = X
|subinterval| = X/n  (n- number of intervals)
Y=X  (Y - nubmber of subinterval sets)

O(X^2)   - not good if implemented naively