确定二叉树的特征。如：每个节点的层次，从根到该节点的枝长（路径长度），子孙的个数及祖先的个数。每个节点在前序、中序、后序中的访问的序号。-To determine the characteristics of a binary tree. Such as: the level of each node from the root to the node branch length (path length), the number of children and grandchildren and the number of ancestors. Each node in the first sequence, the sequence, the order of the access number.