# Python Program to Build Binary Tree if Inorder or Postorder Traversal as Input class BinaryTree:    def __init__(self, key=None):        self.key = key        self.left = None        self.right = None     def set_root(self, key):        self.key = key     def inorder(self):        if self.left is not None:            self.left.inorder()        print(self.key, end=' ')        if self.right is not None:            self.right.inorder()     def postorder(self):        if self.left is not None:            self.left.postorder()        if self.right is not None:            self.right.postorder()        print(self.key, end=' ')  def construct_btree(postord, inord):    if postord == [] or inord == []:        return None    key = postord[-1]    node = BinaryTree(key)    index = inord.index(key)    node.left = construct_btree(postord[:index], inord[:index])    node.right = construct_btree(postord[index:-1], inord[index + 1:])    return node  postord = input('Input post-order traversal: ').split()postord = [int(x) for x in postord]inord = input('Input in-order traversal: ').split()inord = [int(x) for x in inord] btree = construct_btree(postord, inord)print('Binary tree constructed.')print('Verifying:')print('Post-order traversal: ', end='')btree.postorder()print()print('In-order traversal: ', end='')btree.inorder()print()