1.输入带空二叉树(信息)的先序遍历序列，生成一棵二叉树；(若结点为字符类型,用空格表示空二叉树；若结点为整数类型，

用0(零)表示空二叉树)

2.作前序遍历，分别用递归算法、非递归算法实现；

3.作中序遍历，分别用递归算法、非递归算法实现；

4.作后序遍历，用递归算法实现；

5.求度分别为0、1、2的结点的数目,分别用递归算法、非递归

算法实现；

6.按层次遍历二叉树(提示：使用一个队列实现）；

7.求二叉树的高度(深度)；

-1. Enter with empty binary tree (information) of the first traversal sequence to generate a binary tree　(if the node for the character type of binary tree by a space, said space　node if an integer type, with 0 (zero) that the empty tree) 2. for the pre-order traversal, recursive algorithm, respectively, non-recursive algorithm　3. for in order traversal, recursive algorithm, respectively, non-recursive algorithm　4. traversal sequence for the latter, the recursive algorithm　5. 0,1,2 respectively for the number of nodes, respectively, using recursive algorithms, non-recursive algorithm　6. traversal according to the level of the Second-tree (hint: use a queue to achieve)　7. for tree height (depth)