RhodeCode

    int index(const Node& node) const { return node._id; }

    Arc arc(const Node& s, const Node& t) const {

      return Arc(s._id * _node_num + t._id);

    }

    int nodeNum() const { return _node_num; }

    int arcNum() const { return _arc_num; }

    int maxNodeId() const { return _node_num - 1; }

    int maxArcId() const { return _arc_num - 1; }

    Node source(Arc arc) const { return arc._id / _node_num; }

    Node target(Arc arc) const { return arc._id % _node_num; }

    static int id(Node node) { return node._id; }

    static int id(Arc arc) { return arc._id; }

    static Node nodeFromId(int id) { return Node(id);}

    static Arc arcFromId(int id) { return Arc(id);}

    typedef True FindArcTag;

    Arc findArc(Node s, Node t, Arc prev = INVALID) const {

    }

    class Node {

      friend class FullDigraphBase;

    protected:

      int _id;

      Node(int id) : _id(id) {}

    public:

      Node() {}

      Node (Invalid) : _id(-1) {}

      bool operator==(const Node node) const {return _id == node._id;}

      bool operator!=(const Node node) const {return _id != node._id;}

      bool operator<(const Node node) const {return _id < node._id;}

    };

    class Arc {

      friend class FullDigraphBase;

    protected:

      int _id;  // _node_num * source + target;

      Arc(int id) : _id(id) {}