How do I implement an AVL tree in Python?

How do I implement an AVL tree in Python?

To implement an AVL tree in Python, you need to create a class for the tree and define methods for insertion, deletion, and balancing.

Can you show me the code for inserting a node?

Sure! Here's a basic implementation of the insert method:

class AVLTree:
    def insert(self, root, key):
        # Perform normal BST insert
        if not root:
            return Node(key)
        elif key < root.key:
            root.left = self.insert(root.left, key)
        else:
            root.right = self.insert(root.right, key)

        # Update the balance factor and balance the tree
        return self.balance(root)

What about balancing the tree after insertion?

After insertion, you need to check the balance factor of each node and perform rotations if necessary. Here's a simple example:

def balance(self, root):
    balance = self.get_balance(root)
    
    # Left Left Case
    if balance > 1 and key < root.left.key:
        return self.right_rotate(root)
    
    # Right Right Case
    if balance < -1 and key > root.right.key:
        return self.left_rotate(root)
    
    # Left Right Case
    if balance > 1 and key > root.left.key:
        root.left = self.left_rotate(root.left)
        return self.right_rotate(root)
    
    # Right Left Case
    if balance < -1 and key < root.right.key:
        root.right = self.right_rotate(root.right)
        return self.left_rotate(root)
    
    return root