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#ifndef GRAPH_H
#define GRAPH_H

#include <QLinkedList>
#include <QHash>
#include <QString>

/// A graph that can have their nodes topologically sorted.
class Graph
{
public:
    /// Create a new graph with \p numNodes nodes.
    Graph(int numNodes);
    ~Graph();

    /// Returns the numbed of nodes in this graph.
    int nodeCount() const;
    /// Returns true if the graph contains the edge from -> to
    bool containsEdge(int from, int to);
    /// Adds an edge to this graph.
    void addEdge(int from, int to);
    /// Removes an edge out of this graph.
    void removeEdge(int from, int to);
    /// Print this graph to stdout.
    void dump() const;
    /**
    *   Dumps a dot graph to a file named \p filename.
    *   \param nodeNames map used to translate node ids to human readable text.
    *   \param fileName file name where the output should be written.
    */
    void dumpDot(const QHash<int, QString>& nodeNames, const QString& fileName) const;

    /**
    *   Topologically sort this graph.
    *   \return A collection with all nodes topologically sorted or an empty collection if a ciclic dependency was found.
    */
    QLinkedList<int> topologicalSort() const;
private:

    struct GraphPrivate;
    GraphPrivate* m_d;
};

#endif