/** \file
 * \brief Declaration of class DfsAcyclicSubgraph
 *
 * \author Carsten Gutwenger
 *
 * \par License:
 * This file is part of the Open Graph Drawing Framework (OGDF).
 *
 * \par
 * Copyright (C)<br>
 * See README.md in the OGDF root directory 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, see
 * http://www.gnu.org/copyleft/gpl.html
 */

#pragma once

#include <ogdf/basic/GraphAttributes.h>
#include <ogdf/layered/AcyclicSubgraphModule.h>

namespace ogdf {

//! DFS-based algorithm for computing a maximal acyclic subgraph.
/**
 * The algorithm simply removes all DFS-backedges and works in linear-time.
 */
class OGDF_EXPORT DfsAcyclicSubgraph : public AcyclicSubgraphModule {
public:
	//! Computes the set of edges \p arcSet, which have to be deleted in the acyclic subgraph.
	virtual void call(const Graph& G, List<edge>& arcSet) override;

	//! Call for UML graph.
	/**
	 * Computes the set of edges \p arcSet, which have to be deleted
	 * in the acyclic subgraph.
	 */
	void callUML(const GraphAttributes& AG, List<edge>& arcSet);

private:
	int dfsFindHierarchies(const GraphAttributes& AG, NodeArray<int>& hierarchy, int i, node v);

	void dfsBackedgesHierarchies(const GraphAttributes& AG, node v, NodeArray<int>& number,
			NodeArray<int>& completion, int& nNumber, int& nCompletion);
};

}
