Invert Binary Tree

LeetCode: https://leetcode.com/problems/invert-binary-tree/

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

1def invertTree(root: Optional[TreeNode]) -> Optional[TreeNode]:
2    if not root:
3        return None
4    root.left, root.right = root.right, root.left
5    invertTree(root.left)
6    invertTree(root.right)
7    return root
Previous
Maximum Depth of Binary Tree
Next
Validate Binary Search Tree
node
4
0
7
1
2
2
1
3
3
4
6
5
9
6
tree=[4, 7, 2, 1, 3, 6, 9]
Step 1 / 4
Step 1:
At root=4, swap its left and right children.
Pointers: node=0
Focus: swap @ [0]