{

public:

MergeFeature(double weight=1);

~MergeFeature();

// implement interface

virtual void save_tuple(ofstream& fout) const;

virtual void load_tuple(ifstream& fin);

protected:

unsigned long long get_index(const unsigned long long& game_board) const;

int get_isomorphic_indexes(const unsigned long long& original_index, unsigned long long* isomorphic_indexes) const;