std::vector< bool, ModelAlloc<bool> > explored_children;
std::vector< bool, ModelAlloc<bool> > backtrack;
std::vector< struct fairness_info, ModelAlloc< struct fairness_info> > fairness;
std::vector< bool, ModelAlloc<bool> > explored_children;
std::vector< bool, ModelAlloc<bool> > backtrack;
std::vector< struct fairness_info, ModelAlloc< struct fairness_info> > fairness;