pds-fix.cpp

            auto search(std::string const& source, std::string const& goal) -> void
            {
                // add is_max_depth_reached to stop the for loop
                bool is_max_depth_reached = false;                        
                for (max_depth_ = 0; is_max_depth_reached; ++max_depth_)
                {
                    is_max_depth_reached = false;
                    visited_.clear();
                    q_.clear();
                    for (q_.push_front(Node(source, "")); !q_.empty(); max_q_length_ = std::max(max_q_length_, q_.size()))
                    {
                        auto curr = q_.front();	q_.pop_front();
                        visited_.insert(curr.state);

                        if (goal == curr.state){ final_path_ = curr.path; return; }
                        if (curr.path.size() >= max_depth_)
                        {
                            is_max_depth_reached = true;  //condition for next max_depth_
                            continue
                        }

                        for (auto make_child : func_dic_.at(curr.state.find('0')))
                        {
                            auto child = make_child(curr);
                            if (visited_.end() == visited_.find(child.state)) q_.push_front(child);
                        }
                    }
                }
            }