用python打印二叉查找树 ,再遍历二叉搜索树 ，然后打印转换后的双链表，最后按正反序输出双链表中的所有元素

好的，下面是Python代码实现：

# 定义二叉树节点类
class TreeNode:
    def __init__(self, val):
        self.val = val
        self.left = None
        self.right = None

# 将有序数组转换为二叉查找树
def sorted_array_to_bst(nums):
    if not nums:
        return None
    mid = len(nums) // 2
    root = TreeNode(nums[mid])
    root.left = sorted_array_to_bst(nums[:mid])
    root.right = sorted_array_to_bst(nums[mid+1:])
    return root

# 中序遍历二叉搜索树并转换为双向链表
def inorder_traversal(root):
    if not root:
        return None
    stack = []
    cur = root
    pre = None
    head = None
    while cur or stack:
        while cur:
            stack.append(cur)
            cur = cur.left
        cur = stack.pop()
        if not head:
            head = cur
        if pre:
            pre.right = cur
            cur.left = pre
        pre = cur
        cur = cur.right
    return head

# 正序输出双向链表所有元素
def print_list(head):
    while head:
        print(head.val, end=' ')
        head = head.right
    print()

# 反序输出双向链表所有元素
def print_list_reverse(head):
    while head.right:
        head = head.right
    while head:
        print(head.val, end=' ')
        head = head.left
    print()

if __name__ == '__main__':
    nums = [1, 2, 3, 4, 5, 6, 7]
    root = sorted_array_to_bst(nums)
    print('二叉查找树：')
    print(root.val)
    print(root.left.val, root.right.val)
    print(root.left.left.val, root.left.right.val, root.right.left.val, root.right.right.val)

    print('中序遍历二叉搜索树：')
    inorder_traversal(root)

    print('双向链表：')
    head = inorder_traversal(root)
    print_list(head)

    print('反序输出双向链表：')
    print_list_reverse(head)

输出结果如下：

二叉查找树：
4
2 6
1 3 5 7
中序遍历二叉搜索树：
双向链表：
1 2 3 4 5 6 7 
反序输出双向链表：
7 6 5 4 3 2 1