LC 0637 [E] Average of Levels in Binary Tree - ALawliet/algorithms GitHub Wiki

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def averageOfLevels(self, root: TreeNode) -> List[float]:
        res = []
        if root is None: return res
        Q = deque([root])
        while Q:
            levelSize = len(Q)
            levelSum = 0.0
            for _ in range(levelSize):
                node = Q.popleft()
                levelSum += node.val
                if node.left:
                    Q.append(node.left)
                if node.right:
                    Q.append(node.right)
            res.append(levelSum / levelSize)
        return res