LC226 - Invert Binary Tree

Problem

Given the root of a binary tree, invert the tree, and return its root.

Example

Input: root = [4,2,7,1,3,6,9]

Output: [4,7,2,9,6,3,1]

Solution

def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
	if not root:
		return None
	
	tmp = root.left
	root.left = root.right	
	root.right = tmp

	self.invertTree(root.left)
	self.invertTree(root.right)
	
	return root