// © Copyright 1997. Joseph Bergin. All rights reserved.

#ifndef Graph_H
#define Graph_h

#include <pair.h>
#include "vector.h"

template <class T>
class GraphNode
{	public:	
		T value;
	private:
		int _index;
		GraphNode(const T&t = T()):value(t), _index(-1){}
		GraphNode(const T&t, int index):value(t), _index(index){}

	friend class DiGraph<T>;
//	friend ostream& operator<<(ostream&, const GraphNode<T>&);
	friend class  pair<GraphNode<T>, vector<int> >; // To initialize an array.
};

template <class T>
ostream& operator<<(ostream& os, const GraphNode<T>& gn)
{	os << gn.value;
	return os;
}

template <class T>
class DiGraph
{	public:
		typedef vector< pair<GraphNode<T>, vector<int> > >::iterator iterator;
		
		DiGraph():_vertices(){}
		
		GraphNode<T> & newGraphNode(const T& t)
		{	_vertices.push_back
				(	pair <GraphNode<T>, vector<int> >
					(	GraphNode<T>(t, _vertices.size()), vector<int>() 
					) 
				);
			return _vertices.back().first;
		}
		
		void arc(const GraphNode<T>& from, const GraphNode<T>& to)
		{	_vertices[from._index].second.push_back(to._index);
		}

		iterator begin(){ return _vertices.begin();}
		iterator end (){ return _vertices.end();}
		
	private:
		vector< pair<GraphNode<T>, vector<int> > > _vertices;
		
};

#endif