Fix a problem of underflow causing wrong hit order

      if (mm_positive_hits[mi].size() == 0) continue;

      // only the positive part may have the underflow issue

      if (heap_resort)

        std::sort(mm_positive_hits[mi].begin(), mm_positive_hits[mi].end());

        std::sort(mm_positive_hits[mi].begin(), mm_positive_hits[mi].end(), CompSortHits);

      struct mmHit nh;

      nh.mi = mi;

      nh.position = mm_positive_hits[mi][0];

    delete[] mm_negative_hits;

    delete[] mm_pos;

  } else {

    std::sort(positive_hits.begin(), positive_hits.end());

    std::sort(positive_hits.begin(), positive_hits.end(), CompSortHits);

    std::sort(negative_hits.begin(), negative_hits.end());

  }

  /*for (uint32_t mi = 0 ; mi < positive_hits->size() ; ++mi)

    return key;

  }

  inline static bool CompSortHits(const uint64_t &a, const uint64_t &b) {

    if (int(a>>32) != int(b>>32))

      return a < b;

    else

      return (int)a < int(b);

  }

 protected:

  int kmer_size_;

  int window_size_;

    repetitive_seed_length_ = 0;

  }

  inline void PrintCandidates(FILE *fp) {

    uint32_t i ;

    for (i = 0 ; i < positive_candidates_.size() ; ++i)

      fprintf(fp, "+ %d %d %d %d\n", i, (int)(positive_candidates_[i].position>>32), (int)(positive_candidates_[i].position), positive_candidates_[i].count) ;

    for (i = 0 ; i < negative_candidates_.size() ; ++i)

      fprintf(fp, "- %d %d %d %d\n", i, (int)(negative_candidates_[i].position>>32), (int)(negative_candidates_[i].position), negative_candidates_[i].count) ;

  }

  inline size_t GetNumCandidates() const {

    return positive_candidates_.size() + negative_candidates_.size();

  }

  bool operator<(const mmHit &h) const {

    // the inversed direction is to make a min-heap

    //return position > h.position;

    if (int(position>>32) != int(h.position>>32))

      return position > h.position;

    else

      return (int)position > (int)h.position;

  }

};