#!/usr/bin/perl
#with graph
use strict; use warnings; use Data::Dumper;
use Graph;
my $g =Graph::Undirected->new;

my @a=(1,1,2,3,4,4,8,8);
my @b=(3,4,3,5,6,7,9,10); 
    
for ( 0 .. $#a){
    $g->add_edge($a[$_], $b[$_]);
}   
print Dumper $g->connected_components;
__DATA__
this prints ...$VAR1 = [
          9,
          8,
          10
        ];
$VAR2 = [
          6,
          4,
          1,
          3,
          2,
          5,
          7
        ];