/*
 * $Revision: 2559 $
 *
 * last checkin:
 *   $Author: gutwenger $
 *   $Date: 2012-07-06 15:04:28 +0200 (Fri, 06 Jul 2012) $
 ***************************************************************/

/** \file
 * \brief Declaration of class Set.
 *
 * \author Stefan Hachul
 *
 * \par License:
 * This file is part of the Open Graph Drawing Framework (OGDF).
 *
 * \par
 * Copyright (C)<br>
 * See README.txt in the root directory of the OGDF installation for details.
 *
 * \par
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * Version 2 or 3 as published by the Free Software Foundation;
 * see the file LICENSE.txt included in the packaging of this file
 * for details.
 *
 * \par
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * \par
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * \see  http://www.gnu.org/copyleft/gpl.html
 ***************************************************************/

#ifdef _MSC_VER
#pragma once
#endif

#ifndef OGDF_SET_H
#define OGDF_SET_H

#include <ogdf/basic/List.h>
#include <ogdf/basic/Graph.h>
#include <ogdf/basic/NodeArray.h>
#include <ogdf/internal/energybased/NodeAttributes.h>

namespace ogdf {

	class Set
	{
		//Helping data structure that holds set S_node of nodes in the range [0,
		//G.number_of_nodes()-1] (needed for class Multilevel) for randomly choosing nodes
		//(with uniform or weighted probability!)

	public:

		Set();     //constructor
		~Set();    //destructor

		void set_seed(int rand_seed); //the the random seed to rand_seed


		//---------------------- for set of nodes---------------------------------------

		//Inits S_node[0,...,G.number_of_nodes()-1] and stores the i-th node of P
		//at position S_node[i] and in position_in_node_set for each node its index in
		//S_node.
		void init_node_set(Graph& G);

		//Returns whether S_node is empty or not.
		bool empty_node_set();

		//Returns true if and only if v is deleted from S_node.
		bool is_deleted(node v);

		//Deletes the node v from S_node.
		void delete_node(node v);

		//---------------- for set of nodes with uniform probability -------------------


		//Selects a random element from S_node with uniform probability and updates S_node
		//and position_in_node_set.
		node get_random_node();

		//---------------- for set of nodes with weighted  probability -------------------

		//Same as init_node_set(G), but additionally the array mass_of_star is caculated.
		void init_node_set(Graph& G,NodeArray<NodeAttributes>& A);

		//---------------- for set of nodes with ``lower mass'' probability --------------

		//Gets rand_tries random elements from S_node and selects the one with the lowest
		//mass_of_star and updates S_node and position_in_node_set.
		node get_random_node_with_lowest_star_mass(int rand_tries);

		//---------------- for set of nodes with ``higher mass'' probability --------------

		//Gets rand_tries random elements from S_node and selects the one with the highest
		//mass_of_star and updates S_node and position_in_node_set.
		node get_random_node_with_highest_star_mass(int rand_tries);

	private:

		bool using_S_node; //indicates weather S_item, or S_node is used

		node* S_node;       //representation of the node set S_node[0,G.number_of_nodes()-1]
		int last_selectable_index_of_S_node;//index of the last randomly choosable element
		//in S_node (this value is decreased after each
		//select operation)
		NodeArray<int> position_in_node_set;//holds for each node of G the index of its
		//position in S_node
		NodeArray<int> mass_of_star; //the sum of the masses of a node and its neighbours

	};

}//namespace ogdf
#endif


