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This artifact contains several miscellaneous, well-known algorithms, which however are rather specific in their concrete use case and therefore not fit for the AutomataLib Utilities library. Examples include Dijkstra's algorithm for the SSSP problem, the Floyd-Warshall algorithm for the APSP problem and Tarjan's algorithm for finding all strongly-connected components in a graph.

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/* Copyright (C) 2013 TU Dortmund
 * This file is part of AutomataLib, http://www.automatalib.net/.
 * 
 * AutomataLib is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 3.0 as published by the Free Software Foundation.
 * 
 * AutomataLib 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with AutomataLib; if not, see
 * http://www.gnu.de/documents/lgpl.en.html.
 */
package net.automatalib.algorithms.graph.scc;

import java.util.List;

import net.automatalib.graphs.Graph;
import net.automatalib.util.graphs.traversal.GraphTraversal;

/**
 * Algorithms for finding strongly-connected components (SCCs) in a graph.
 * 
 * @author Malte Isberner 
 *
 */
public abstract class SCCs {

	private SCCs() {
	}
	
	
	/**
	 * Find all strongly-connected components in a graph. When a new SCC is found, the
	 * {@link SCCListener#foundSCC(java.util.Collection)} method is invoked. The listener
	 * object may hence not be null.
	 * 
	 * Tarjan's algorithm is used for realizing the SCC search.
	 * 
	 * @param graph the graph
	 * @param listener the SCC listener
	 * 
	 * @see TarjanSCCVisitor
	 */
	public static  void findSCCs(Graph graph, SCCListener listener) {
		TarjanSCCVisitor vis = new TarjanSCCVisitor<>(graph, listener);
		for(N node : graph) {
			if(!vis.hasVisited(node))
				GraphTraversal.depthFirst(graph, node, vis);
		}
	}
	
	/**
	 * Collects all strongly-connected components in a graph. The SCCs are returned as
	 * a list of lists.
	 * 
	 * Tarjan's algorithm is used for realizing the SCC search.
	 * 
	 * @param graph the graph
	 * @return a list of all SCCs, each represented as a list of its nodes
	 * 
	 * @see TarjanSCCVisitor
	 */
	public static  List> collectSCCs(Graph graph) {
		SCCCollector coll = new SCCCollector<>();
		findSCCs(graph, coll);
		return coll.getSCCList();
	}

}