由用户输入先序和中序序列，以此构造一棵二叉树；然后对二叉树进行层次遍历，先序中序后序遍历；并且计算出这棵树的第一条最长路径并将其打印出来。-By the user input sequence and the first order sequence as a binary tree structure then the level of binary tree traversal, inorder postorder preorder traversal and calculate the