Symmetric Tree
Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).
Follow up: Could you solve it both recursively and iteratively?
Example 1
1
/ \
2 2
/ \ / \
3 4 4 3Input
root = [1,2,2,3,4,4,3]Output
trueThe tree is symmetric around its center.
Example 2
1
/ \
2 2
\ \
3 3Input
root = [1,2,2,null,3,null,3]Output
falseThe tree is not symmetric because the null and non-null child positions do not mirror each other.
Constraints
- The number of nodes in the tree is in the range
[1, 1000]. -100 <= Node.val <= 100