Method pop

include/rabitqlib/utils/buffer.hpp:59–67

get unchecked candidate with minimum distance

    // get unchecked candidate with minimum distance
    PID pop() {
        PID cur_id = data_[cur_].id;
        set_checked(data_[cur_].id);
        ++cur_;
        while (cur_ < size_ && is_checked(data_[cur_].id)) {
            ++cur_;
        }
        return cur_id;
    }

    void clear() {
        size_ = 0;