| English | 简体中文 |
root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).
Input: root = [1,2,2,3,4,4,3] Output: true
Input: root = [1,2,2,null,3,null,3] Output: false
- The number of nodes in the tree is in the range
-100 <= Node.val <= 100
Follow up: Could you solve it both recursively and iteratively?