Python describe LeetCode 515. Find the maximum in each tree row

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subject

Given the root node of a binary tree root , Please find the maximum value of each layer in the binary tree .

Example 1：

 Input : root = [1,3,2,5,3,null,9]
Output : [1,3,9]

Example 2：

 Input : root = [1,2,3]
Output : [1,3]

Tips ：

• The range of the number of nodes in a binary tree is [0,104]
• -231 <= Node.val <= 231 - 1

Python describe

Level traversal

# 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 largestValues(self, root: Optional[TreeNode]) -> List[int]:
if not root:
return []
res = []
q = [root]
while q:
tmp_max,n = q[0].val,len(q)
for i in range(n):
node = q[0]
tmp_max = max(node.val,tmp_max)
q.remove(q[0])
if node.left:
q.append(node.left)
if node.right:
q.append(node.right)
res.append(tmp_max)
return res