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226. Invert Binary Tree

Tree Depth-First Search Breadth-First Search Binary Tree

Problem - Invert Binary Tree

Easy

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

Solutions

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        if root is None:
            return None

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

Submission Stats:

  • Runtime: 0 ms (100.00%)
  • Memory: 17.9 MB (9.54%)