按先序扩展序列建立二叉树，先序、中序、后序遍历的递归算法，二叉树遍历的非递归算法，层次的非递归算法，求二叉树的深度。-sequence extended by the first sequence established binary tree, first sequence, sequence, after the preorder the recursive algorithm, the binary tree traversal non - recursive algorithm, the level of non - recursive algorithm for binary tree depth.