Method IsAncestorOf

cpp/src/arrow/dataset/forest_internal.h:76–78

    int num_descendants() const { return forest->descendant_counts_->at(i); }

    bool IsAncestorOf(const Ref& ref) const {
      return i < ref.i && i + 1 + num_descendants() > ref.i;
    }

    explicit operator bool() const { return forest != NULLPTR; }