« 问题描述：

按前序列出二叉树各结点为根的子树的结点数。

　　« 实验任务：

对于给定的二叉树，计算二叉树各结点为根的子树的结点数，并按前序列出。

-« Descr iption of the problem: According to the former sequence of binary tree nodes for each sub-tree root nodes. « Experimental task: For a given binary tree, binary tree calculation for each node of the subtree root nodes, and the former sequence.