TDAT:     private void remove(int index) {
        assert(!isLeaf());
        totalCount -= children[index].totalCount;
        for (int i = index + 1; i < count; ++i) {
            entries[i - 1] = entries[i];
            children[i - 1] = children[i];
        }
        entries[count - 1] = null;
        children[count - 1] = null;
        --count;
    }
 COM: <s> remove a entry child pair </s>