#!/usr/bin/env python3

# -*- encoding: utf-8 -*-

"""

@FileName : binaryTreeLevelOrderTraversal.py

@Author : 56

@Date : 2020/5/13

@Description: https://leetcode-cn.com/problems/binary-tree-level-order-traversal/

"""

from typing import List

# Definition for a binary tree node.

class TreeNode:

def __init__(self, x):

self.val = x

self.left = None

self.right = None

class Solution:

def levelOrder(self, root: TreeNode) -> List[List[int]]:

if root is None: return []

result: List[List[int]] = []

queue: List[TreeNode] = [root]

while len(queue) != 0:

values: List[int] = []

newQueue: List[TreeNode] = []

for node in queue:

values.append(node.val)

if node.left is not None: newQueue.append(node.left)

if node.right is not None: newQueue.append(node.right)

result.append(values)

queue = newQueue

return result