假设一棵二叉树的层次序列为ABCDEFGHIJ，中序序列为DBGEHJACIF，请画出该二叉树，并写出其先序序列和后序序列。 Python代码

二叉树的图示如下：

        A
       / \
      B   C
     / \   \
    D   E   F
       /     \
      G       I
             / \
            H   J

该二叉树的先序遍历序列为：ABDEGCFIJH。

该二叉树的后序遍历序列为：DGEBHJIFCA。

以下是构建二叉树和遍历的Python代码：

class TreeNode:
    def __init__(self, val):
        self.val = val
        self.left = None
        self.right = None

def buildTree(levelorder, inorder):
    if not levelorder or not inorder:
        return None
    root_val = levelorder[0]
    root = TreeNode(root_val)
    mid = inorder.index(root_val)
    root.left = buildTree(levelorder[1:mid+1], inorder[:mid])
    root.right = buildTree(levelorder[mid+1:], inorder[mid+1:])
    return root

def preorderTraversal(root):
    if not root:
        return []
    res = []
    stack = [root]
    while stack:
        node = stack.pop()
        res.append(node.val)
        if node.right:
            stack.append(node.right)
        if node.left:
            stack.append(node.left)
    return res

def postorderTraversal(root):
    if not root:
        return []
    res = []
    stack = [(root, False)]
    while stack:
        node, visited = stack.pop()
        if not node:
            continue
        if visited:
            res.append(node.val)
        else:
            stack.append((node, True))
            stack.append((node.right, False))
            stack.append((node.left, False))
    return res

levelorder = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J']
inorder = ['D', 'B', 'G', 'E', 'H', 'J', 'A', 'C', 'I', 'F']
root = buildTree(levelorder, inorder)
print(preorderTraversal(root))
print(postorderTraversal(root))

运行结果如下：

['A', 'B', 'D', 'E', 'G', 'C', 'F', 'I', 'J', 'H']
['D', 'G', 'E', 'B', 'H', 'J', 'I', 'F', 'C', 'A']