Description
Given the root of a binary tree, invert the tree, and return its root. Inverting a binary tree means swapping the left and right children of all nodes in the tree.
Examples
Input:
root = [4,2,7,1,3,6,9]Output:
[4,7,2,9,6,3,1]Explanation:
At each node, left and right subtrees are swapped. Root 4's children swap (2,7 becomes 7,2), then recursively: 7's children become (9,6) and 2's children become (3,1).
Input:
root = [2,1,3]Output:
[2,3,1]Explanation:
The root node 2 has left child 1 and right child 3. After inversion, these swap positions: left becomes 3, right becomes 1.
Input:
root = []Output:
[]Explanation:
An empty tree has no nodes to invert, so the result is an empty tree.
Constraints
- •
The number of nodes in the tree is in the range [0, 100] - •
-100 ≤ Node.val ≤ 100