Introduction

In this blog post, we will explore how to solve the LeetCode problem "226" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Given the root of a binary tree, invert the tree, and return its root. Example 1: Input: root = [4,2,7,1,3,6,9] Output: [4,7,2,9,6,3,1] Example 2: Input: root = [2,1,3] Output: [2,3,1] Example 3: Input: root = [] Output: [] Constraints: The number of nodes in the tree is in the range [0, 100]. -100 <= Node.val <= 100

Explanation

Here's the breakdown of the solution:

• Recursive Approach: Use recursion to traverse the tree. At each node, swap the left and right children.
• Base Case: If the node is None, return None.

• Return Root: After inverting the subtree, return the original root.

• Time Complexity: O(N), where N is the number of nodes in the tree.

• Space Complexity: O(H) in the worst case (skewed tree), where H is the height of the tree, due to the recursion stack. In the average case (balanced tree), it would be O(log N).

Code

    class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def invertTree(root: TreeNode) -> TreeNode:
    """
    Inverts a binary tree.

    Args:
        root: The root of the binary tree.

    Returns:
        The root of the inverted binary tree.
    """
    if root is None:
        return None

    # Swap left and right children
    root.left, root.right = root.right, root.left

    # Recursively invert the left and right subtrees
    invertTree(root.left)
    invertTree(root.right)

    return root