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Invert Binary Tree

Problem Statement​

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

Leetcode Link

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

Code​

Python Code

class Solution(object):
    def invertTree(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        if not root:
        return None
        root.left,root.right=root.right,root.left
        self.invertTree(root.left)
        self.invertTree(root.right)
        return root