- Container *container = 0;
- std::list<Slot *> slots;
- unsigned n_active_slots = 0;
- unsigned n_slack_vars[2] = { 0, 0 };
+ Container *container = nullptr;
+ std::vector<std::unique_ptr<Slot>> slots;
+ std::size_t n_active_slots = 0;
+ std::size_t n_slack_vars[2] = { 0, 0 };