---
tags: leetcode
---

# [429. N-ary Tree Level Order Traversal](https://leetcode.com/problems/n-ary-tree-level-order-traversal/)
---
# My Solution
## The Key Idea for Solving This Coding Question
BFS
## C++ Code

/*
// 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<vector<int>> levelOrder(Node *root) {
        if (root == nullptr) {
            return {};
        }

        queue<Node *> q;
        vector<vector<int>> answer;

        q.push(root);
        while (!q.empty()) {
            int qLen = q.size();
            vector<int> oneLevel;

            for (int i = 0; i < qLen; ++i) {
                Node *curr = q.front();
                q.pop();

                oneLevel.push_back(curr->val);

                for (Node *child : curr->children) {
                     q.push(child);
                }
            }
            answer.push_back(oneLevel);
        }

        return answer;
    }
};

## Time Complexity
$O(n)$
$n$ is the number of nodes in the n-ary tree referred by `root`.
## Space Complexity
$O(n)$
$n$ is the number of nodes in the n-ary tree referred by `root`.
# Miscellane
<!--
# Test Cases

[1,null,3,2,4,null,5,6]

[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]

[]

-->