# ---
# title: 589. N-ary Tree Preorder Traversal
# id: problem589
# author: Tian Jun
# date: 2020-10-31
# difficulty: Easy
# categories: Tree
# link: <https://leetcode.com/problems/n-ary-tree-preorder-traversal/description/>
# hidden: true
# ---
# 
# Given 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)._
# 
# 
# 
# **Follow up:**
# 
# Recursive solution is trivial, could you do it iteratively?
# 
# 
# 
# **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]
#     
# 
# 
# 
# **Constraints:**
# 
#   * The height of the n-ary tree is less than or equal to `1000`
#   * The total number of nodes is between `[0, 10^4]`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
