#!/usr/bin/perl
use warnings;
use strict;


my $couldy=['cloudy','t','f']; # 'cloudy' is the node name and 't','f' are the values this node can assume. Likewise for other nodes.
my $sprinkler=['sprinkler','t','f'];
my $rain=['rain','t','f'];
my $wetgrass=['wetgrass','t','f'];
my $values=[$sprinkler,$couldy,$rain,$wetgrass]; 


my @nodes=('sprinkler','cloudy','wetgrass','rain');

foreach my $i (@nodes) {
	my $nodeparents=[parentchildrelationship($i)];
	print "$i $nodeparents $values\n";
	my $hash1=cpt($i,$nodeparents,$values);

	foreach my $i (keys %{$hash1}) {
		print "$i=>${$hash1}{$i}\n";
		#print "$i\n";
	}
}


sub cpt {
	my $node=$_[0];
	my @parents=@{$_[1]};
	my @nodevalues=@{$_[2]};
	my %hash=();
	my @nodeindex=();
	my @temparray=();
	my $string="";
	my @temp=();
	my $s;

	foreach my $i (@parents) {
		for (my $j=0;$j<=$#nodevalues;$j++) {
				if ($i eq ${$nodevalues[$j]}[0]) {
					push (@nodeindex, $j); 
				}
		}
	}
	
	foreach my $i (reverse @nodeindex) { 
		push (@temparray, $nodevalues[$i]); 
	}

	for (my $i=0;$i<=$#temparray;$i++) {
		$string="$string"."${$temparray[$i]}[0] "; 
		shift @{$temparray[$i]};
		$temp[$i]=join (",",@{$temparray[$i]});
	}

	$hash{$string}=1; #fill %hash with the header (header is simply the name of the node along with its parents)
	$s = join "\\ ", map "{$_}", @temp;
	#print "$s\n";
	$hash{$_}=1 for glob $s; 
	
	return {%hash}; 
	
	$node="";
	@parents=(); 
	@nodevalues=();
	%hash=();
	@nodeindex=();
	@temparray=();
	$string="";
	@temp=();
	$s="";
}


sub parentchildrelationship {

	my $node=$_[0]; #or use "shift"
	my %parentchild=();
	my @nodeset=();

	%parentchild=('cloudy'=>['none'], 'sprinkler'=>['cloudy'], 'rain'=>['cloudy'], 'wetgrass'=>['rain','sprinkler']); #This is the structure of the graph, for example node 'cloudy' has no parent; node 'sprinkler' has 'cloudy' as its parents;  node 'rain' has 'cloudy' as its parents;  node 'weygrass' has 'rain' and 'sprinkler' as its parents; (directionality of the arrow determines the child-parent relationship).
	push (@nodeset, $node, @{$parentchild{$node}}); 
	return @nodeset;
}