struct Step {
Board board;
std::shared_ptr<Step> prev;
- std::vector<Step*> successors(std::shared_ptr<Step> shared_this);
+ std::vector<Step*> successors(std::shared_ptr<Step> shared_this) const;
static signed char adjacent[BOARD_SIZE][5];
};
std::ostream& operator<<(std::ostream& os, const Step& step);