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LeetCode solutions

101. Symmetric Tree

My accepted Python solution to LeetCode problem 101, Symmetric Tree, running in 5ms.

  • Difficulty: Easy
  • Python
  • Runtime 5ms
  • Memory 12.6MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 5ms, memory 12.6MB, accepted 2025-12-23.

python
class Solution(object):
    def isSymmetric(self, root):
        """
        :type root: Optional[TreeNode]
        :rtype: bool
        """
        def isMirror(left, right):
            if not left and not right:
                return True
            if not left or not right:
                return False
            return (left.val == right.val and 
                    isMirror(left.left, right.right) and 
                    isMirror(left.right, right.left))
        return isMirror(root.left, root.right) if root else True

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