Prohledávání do hloubky

    /**
     * Dosud neobjeveny uzel
     */
    private static final int FRESH = 0;
    /**
     * Otevreny uzel
     */
    private static final int OPENED = 1;
    /**
     * Uzavreny uzel
     */
    private static final int CLOSED = 2;

    /**
     * Prohledavani do hloubky (rekurzivne)
     * @param graph
     */
    public static void depthFirstSearch(GraphIface graph){
        //Stavy jednotlivych uzlu
        int[] state = new int[graph.getVertexCount()];

        for(int i = 0; i < state.length; i++) state[i] = FRESH;
        //zajisti pruchod vsemi komponentami souvislosti
        for(int i = 0; i < graph.getVertexCount(); i++){
            if(state[i] == FRESH) doDFS(graph, i, state);
        }
    }
    /**
     * Provede prohledavani do hloubky
     * @param graph graf
     * @param vertexNr cislo uzlu
     * @param state stavy uzlu
     */
    private static void doDFS(GraphIface graph, int vertexNr, int[] state) {
        state[vertexNr] = OPENED;
        List<GraphNodeIface> succ = graph.getNode(vertexNr).getSuccessors();
        for(GraphNodeIface n : succ){
            if(state[n.getId()] == FRESH) doDFS(graph, n.getId(), state);
        }
        state[vertexNr] = CLOSED;
    }

 /**
 * Operace, ktere by mel splnovat graf
 * @author Pavel Micka
 */
public interface GraphIface<ENTITY> {
    /**
     * Prida hranu do grafu
     * @param from uzel, ze ktereho hrana vychazi
     * @param to uzel, do ktereho hrana vede
     */
    public void addEdge(int from, int to);

    /**
     * Vrati pocet hran grafu
     * @return pocet hran grafu
     */
    public int getEdgeCount();

    /**
     * Vrati uzel s danym identifikatorem
     * @param id
     * @return
     */
    public GraphNodeIface getNode(int id);

    /**
     * Vrati pocet vrcholu grafu
     * @return pocet vrcholu grafu
     */
    public int getVertexCount();

    /**
     * Odstrani hranu, v pripade vicenasobneho vyskytu odstrani prvni vyskyt
     * @param from uzel, ze ktereho hrana vychazi
     * @param to uzel, do ktereho hrana vede
     */
    public void removeEdge(int from, int to);

    /**
     * Operace, ktere by mel splnovat uzel grafu
     * @param <ENTITY>
     */
    public interface GraphNodeIface<ENTITY> {
        /**
         * @return the id
         */
        public int getId();

        /**
         * @return the successors
         */
        public List<GraphNodeIface> getSuccessors();

        /**
         * @return the value
         */
        public ENTITY getValue();

        /**
         * @param value the value to set
         */
        public void setValue(ENTITY value);
    }
}