use strict;
use warnings;

my @cons = (
	["1A", "2A"],
	["1A", "2B"],
	["2A", "4A"],
	["3A", "2A"],
	["4A", "5A"],
	["2B", "3A"],
	["3A", "4A"]
);


print "Gib das Element ein, ab welchen der Baum zurueck gegeben werde soll?\n";
my $input_id = <stdin>;
chomp($input_id);
print "--------------------------------\n";
print "--- \n";
print "--- \n";
print "--- Mein input_id war:\n";
print "--- \n";
print "--- $input_id \n";
print "--- \n";
print "--- \n";
print "--------------------------------\n ";



print "IST ---------------\n";
for (my $i = 0; $i <= $#cons; $i++){
	my $id 		=	$cons[$i][0];
	my $rootid 	=	$cons[$i][1];

	
	print "$id --> $rootid\n";
	
	
}

print "\n" x 3;


my @tree_duplicates = ();
&abwaerts($input_id);	
my %seen;
my @tree = grep { ! $seen{join(q{,}, @$_)}++ } @tree_duplicates;
	for (my $i = 0; $i <= $#tree; $i++){
		my $i_id 		=	$tree[$i][0];
		my $i_rootid 	=	$tree[$i][1];
		print "$i_id, $i_rootid\n";
	}


sub abwaerts{

	my $id = shift;
	# print "--> Meine EinstiegsID: $id\n";
	
	for (my $i = 0; $i <= $#cons; $i++){
		my $i_id 		=	$cons[$i][0];
		my $i_rootid 	=	$cons[$i][1];
		# print "ooo $i_id, $i_rootid\n";
		
		if ($id eq $i_id){
				# print "--> in Array iterierend: $i_id\n";
				&abwaerts($i_rootid);
				print "-->CON $id --> $i_rootid\n";
				push @tree_duplicates, [$id, $i_rootid];
		}
	}
}