说明：  在很多常见的财务软件中，科目代码一般都用树型结构来显示。要实现这一点，通常的做法是用多个（嵌套）循环，甚至递归等算法，将科目表中的代码"织"成树，但这样不但算法复杂，而且执行效率低。
(In many common financial software, the subject code is generally used to display the tree structure. To achieve this, the general practice is to use multiple (nested) cycle, and even recursive algorithm, etc., will chart the code woven into a tree, but this algorithm is not only complex and inefficient implementation.)