# [Solved] 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)

## Question

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:

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

Example 2:

```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]
```

Constraints:

• The number of nodes in the tree is in the range `[0, 104]`.
• `0 <= Node.val <= 104`
• The height of the n-ary tree is less than or equal to `1000`.

Follow up: Recursive solution is trivial, could you do it iteratively?

## Python Solution

```"""
# Definition for a Node.
class Node:
def __init__(self, val=None, children=None):
self.val = val
self.children = children
"""

class Solution:
def preorder(self, root: 'Node') -> List[int]:
res = []
stack = [root]

while len(stack)!=0:
x = stack.pop()
if x:
res.append(x.val)
for c in reversed(x.children):
stack.append(c)
return res``` ##### Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

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