# 1. N-ary Tree Preorder Traversal

Given the `root` of an n-ary tree, return *the preorder traversal of its nodes' values*.

Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples)

**Example 1:**

![](https://assets.leetcode.com/uploads/2018/10/12/narytreeexample.png)

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

**Example 2:**

![](https://assets.leetcode.com/uploads/2019/11/08/sample_4_964.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: [1,2,3,6,7,11,14,4,8,12,5,9,13,10]
```

## Solution: (DFS)

```cpp
/*
// Definition for a Node.
class Node {
public:
    int val;
    vector<Node*> children;

    Node() {}

    Node(int _val) {
        val = _val;
    }

    Node(int _val, vector<Node*> _children) {
        val = _val;
        children = _children;
    }
};
*/

class Solution
{
public:
    vector<int> v;
    void traverse(Node *root)
    {

        if (root == NULL)
        {
            return;
        }

        v.push_back(root->val);

        for (int i = 0; i < root->children.size(); i++)
        {
            traverse(root->children[i]);
        }

        return;
    }

    vector<int> preorder(Node *root)
    {

        traverse(root);
        return v;
    }
};
```
