+
+std::vector<Step*> Step::successors(std::shared_ptr<Step> shared_this) {
+ std::vector<Step*> suc;
+ signed char hole_pos = board.hole();
+ for (int i = 0; adjacent[hole_pos][i] > 0; i++) {
+ suc.emplace_back(new Step{board, shared_this});
+ std::swap(suc.back()->board.board[hole_pos], suc.back()->board.board[adjacent[hole_pos][i]]);
+ }
+ return suc;
+}