在Python中实现AVL树

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

class AVLTree:
    def __init__(self):
        self.root = None

    def insert(self, key):
        self.root = self._insert(self.root, key)

    def _insert(self, node, key):
        if node is None:
            return AVLNode(key)
        elif key < node.key:
            node.left = self._insert(node.left, key)
        else:
            node.right = self._insert(node.right, key)

        node.height = 1 + max(self._get_height(node.left), self._get_height(node.right))
        balance_factor = self._get_balance_factor(node)

        if balance_factor > 1:
            if key < node.left.key:
                return self._rotate_right(node)
            else:
                node.left = self._rotate_left(node.left)
                return self._rotate_right(node)
        elif balance_factor < -1:
            if key > node.right.key:
                return self._rotate_left(node)
            else:
                node.right = self._rotate_right(node.right)
                return self._rotate_left(node)

        return node

    def _get_height(self, node):
        if node is None:
            return 0
        return node.height

    def _get_balance_factor(self, node):
        if node is None:
            return 0
        return self._get_height(node.left) - self._get_height(node.right)

    def _rotate_left(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 _rotate_right(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 inorder_traversal(self):
        self._inorder_traversal(self.root)

    def _inorder_traversal(self, node):
        if node:
            self._inorder_traversal(node.left)
            print(node.key)
            self._inorder_traversal(node.right)

tree = AVLTree()
tree.insert(10)
tree.insert(20)
tree.insert(30)
tree.insert(40)
tree.insert(50)
tree.insert(25)

tree.inorder_traversal()

10
20
25
30
40
50