## Description #

Difficulty: **简单**

Related Topics: Tree, Depth-First Search, Breadth-First Search, Binary 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
```

**Constraints:**

- The number of nodes in the tree is in the range
`[1, 1000]`

. `-100 <= Node.val <= 100`

**Follow up:** Could you solve it both recursively and iteratively?

## Solution #

Language: **Go**

IOI