书架数据结构问题

class TreeNode:
    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None
        self.height = 1

class AVLTree:
    def insert(self, root, key):
        if not root:
            return TreeNode(key)
        elif key < root.key:
            root.left = self.insert(root.left, key)
        else:
            root.right = self.insert(root.right, key)

        root.height = 1 + max(self.get_height(root.left), self.get_height(root.right))

        balance = self.get_balance(root)

        if balance > 1 and key < root.left.key:
            return self.right_rotate(root)
        if balance < -1 and key > root.right.key:
            return self.left_rotate(root)
        if balance > 1 and key > root.left.key:
            root.left = self.left_rotate(root.left)
            return self.right_rotate(root)
        if balance < -1 and key < root.right.key:
            root.right = self.right_rotate(root.right)
            return self.left_rotate(root)

        return root

    def left_rotate(self, z):
        y = z.right
        T2 = y.left

        y.left = z
        z.right = T2

        z.height = 1 + max(self.get_height(z.left), self.get_height(z.right))
        y.height = 1 + max(self.get_height(y.left), self.get_height(y.right))

        return y

    def right_rotate(self, z):
        y = z.left
        T3 = y.right

        y.right = z
        z.left = T3

        z.height = 1 + max(self.get_height(z.left), self.get_height(z.right))
        y.height = 1 + max(self.get_height(y.left), self.get_height(y.right))

        return y

    def get_height(self, root):
        if not root:
            return 0
        return root.height

    def get_balance(self, root):
        if not root:
            return 0
        return self.get_height(root.left) - self.get_height(root.right)

# 示例使用
avl_tree = AVLTree()
root = None
books = ["Book A", "Book B", "Book C", "Book D", "Book E"]

for book in books:
    root = avl_tree.insert(root, book)

# 查找书籍
def search_book(root, key):
    if not root or root.key == key:
        return root
    if root.key < key:
        return search_book(root.right, key)
    return search_book(root.left, key)

result = search_book(root, "Book C")
if result:
    print(f"Found book: {result.key}")
else:
    print("Book not found")