数据结构经典实例，深入了解二叉树。如：可查询每个节点的层次，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。-Classic examples of data structures, in-depth understanding of binary tree. Such as: to check the level of each node, the node from the root to shoot length (path length)