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637. Average of Levels in Binary Tree 二叉树每一层的平均值

2024-10-20 15:33:39   214人阅读

Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array.

Example 1:

Input:
    3
   /   9  20
    /     15   7
Output: [3, 14.5, 11]
Explanation:
The average value of nodes on level 0 is 3,  on level 1 is 14.5, and on level 2 is 11. Hence return [3, 14.5, 11].

Note:

  1. The range of node‘s value is in the range of 32-bit signed integer

  1. # Definition for a binary tree node.
  2. # class TreeNode(object):
  3. #     def __init__(self, x):
  4. #         self.val = x
  5. #         self.left = None
  6. #         self.right = None
  8. class Solution(object):
  9.     def averageOfLevels(self, root):
  10.         """
  11.         :type root: TreeNode
  12.         :rtype: List[float]
  13.         """        
  14.         if(not root):
  15.             return 0
  16.         result = []
  17.         queue = [root]
  18.         while(queue):
  19.             count = len(queue)
  20.             sum = 0
  21.             for i in range(0, count):
  22.                 node = queue.pop(0)
  23.                 sum += node.val
  24.                 if(node.left):
  25.                     queue.append(node.left)
  26.                 if(node.right):
  27.                     queue.append(node.right)
  28.             result.append(sum * 1.0 / count)
  29.         return result



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637. Average of Levels in Binary Tree 二叉树每一层的平均值


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