```
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
import queue
class Solution:
def averageOfLevels(self, root):
"""
:type root: TreeNode
:rtype: List[float]
"""
ans = []
q = queue.Queue()
q.put(root)
while not q.empty():
n = q.qsize()
sum0 = 0
for x in range(n):
node = q.get()
sum0 += node.val
if node.left: q.put(node.left)
if node.right: q.put(node.right)
ans.append(sum0/n)
return ans
```