Solved! Leetcode 101. Symmetric Tree


Symmetric Tree

Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).

Example 1:

Input: root = [1,2,2,3,4,4,3]
Output: true

Example 2:

Input: root = [1,2,2,null,3,null,3]
Output: false


  • The number of nodes in the tree is in the range [1, 1000].
  • -100 <= Node.val <= 100

Time complexity:

  • O(n), where n is the number of nodes in a tree, as we need to visit every node in the tree

Space Complexity:

  • O(1)
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