use strict;
use warnings;
use Data::Dumper;

my %dependencies;
while (<DATA>) {
	chomp;
	my ($key, @items) = split /,/;
	$dependencies{$key} = [@items];
}
# print Dumper \%dependencies;

my $continue = 1;
while ($continue) {
	$continue = 0;
	for my $key (keys %dependencies) {
		my @jobs = @{$dependencies{$key}};
		my %seen = map { $_ => 1 } @jobs;
		my @add;
		for my $job (@jobs) {
			next unless exists $dependencies{$job};
			my @new_jobs = @{$dependencies{$job}};
			for my $new_job (@new_jobs) {
				next if exists $seen{$new_job};
				$continue = 1;
				push @add, $new_job;
				$seen{$new_job} = 1;
			}
		}
		push @{$dependencies{$key}}, @add;
	}
}
			
print Dumper \%dependencies;
		


__DATA__
job1,
job2,job1,
job3,job2
job4,job2
job5,job2,job4
job6,jobz
joba,job4,jobb
jobz,jobbc,job2

##</code><code>##

$VAR1 = {
          'job3' => [
                      'job2',
                      'job1'
                    ],
          'jobz' => [
                      'jobbc',
                      'job2',
                      'job1'
                    ],
          'job6' => [
                      'jobz',
                      'jobbc',
                      'job2',
                      'job1'
                    ],
          'job4' => [
                      'job2',
                      'job1'
                    ],
          'joba' => [
                      'job4',
                      'jobb',
                      'job2',
                      'job1'
                    ],
          'job5' => [
                      'job2',
                      'job4',
                      'job1'
                    ],
          'job1' => [],
          'job2' => [
                      'job1'
                    ]
        };