> For the complete documentation index, see [llms.txt](https://shenjunhong.gitbook.io/blog/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://shenjunhong.gitbook.io/blog/suan-fa/2022.3.15.md).

# 2022.3.15

反转二叉树

输入

```
 4
```

/\
2 7 / \ /\
1 3 6 9 输出

```
 4
```

/\
7 2 / \ /\
9 6 3 1 节点的构造函数 /\*\*

* Definition for a binary tree node.
* function TreeNode(val, left, right) {
* ```
  this.val = (val===undefined ? 0 : val)
  ```
* ```
  this.left = (left===undefined ? null : left)
  ```
* ```
  this.right = (right===undefined ? null : right)
  ```
* } \*/

```js
var invertTree = function(root) {
    // 递归 终止条件
    if (root == null) {
        return root
    }
    // 递归的逻辑
    [root.left, root.right] = [invertTree(root.right), invertTree(root.left)]
    return root
}
```