# Given a binary tree, populate an array to represent the averages of all of its levels.
# O(N) space:O(N)
from collections import deque
class TreeNode:
def __init__(self, value) -> None:
self.value = value
self.left = None
self.right = None
def level_average(root):
result = []
if root is None:
return result
queue = deque()
queue.append(root)
while queue:
sum_level = 0.0
level_size = len(queue)
for _ in range(level_size):
current_node = queue.popleft()
sum_level += current_node.value
if current_node.left:
queue.append(current_node.left)
if current_node.right:
queue.append(current_node.right)
result.append(sum_level/level_size)
return result
root = TreeNode(12)
root.left = TreeNode(7)
root.right = TreeNode(1)
root.left.left = TreeNode(9)
root.right.left = TreeNode(10)
root.right.right = TreeNode(5)
print(level_average(root))
# follow up:
# Problem 1: Find the largest value on each level of a binary tree.
# Solution: We will follow a similar approach,
# but instead of having a running value we will track the maximum value of each level.
# maxValue = max(maxValue, currentNode.val)