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# 1522. Diameter of N-Ary Tree

<https://leetcode.com/problems/diameter-of-n-ary-tree>

## Description

Given a `root` of an [N-ary tree](https://leetcode.com/articles/introduction-to-n-ary-trees/), you need to compute the length of the diameter of the tree.

The diameter of an N-ary tree is the length of the **longest** path between any two nodes in the tree. This path may or may not pass through the root.

(*Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value.)*

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/07/19/sample_2_1897.png)

```
**Input:** root = [1,null,3,2,4,null,5,6]
**Output:** 3
**Explanation:** Diameter is shown in red color.
```

**Example 2:**

![](https://assets.leetcode.com/uploads/2020/07/19/sample_1_1897.png)

```
**Input:** root = [1,null,2,null,3,4,null,5,null,6]
**Output:** 4
```

**Example 3:**

![](https://assets.leetcode.com/uploads/2020/07/19/sample_3_1897.png)

```
**Input:** root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14]
**Output:** 7
```

**Constraints:**

* The depth of the n-ary tree is less than or equal to `1000`.
* The total number of nodes is between `[1, 104]`.

## ac

```java
```