515-find-largest-value-in-each-tree-row

1. Find Largest Value in Each Tree Row Solved Medium Topics Companies Given the root of a binary tree, return an array of the largest value in each row of the tree (0-indexed).

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] 10,null,null,11,null,12,null,13,null,null,14] Output: [[1],[2,3,4,5],[6,7,8,9,10],[11,12,13],[14]]

My solution：

"""
# Definition for a Node.
class Node(object):
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""
# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

from collections import deque
class Solution(object):
    def largestValues(self, root):
        """
        :type root: Optional[TreeNode]
        :rtype: List[int]
        """
        if not root:
            return []
        res = []
        queue = deque()
        queue.append(root)
        while queue:
            max_val = float('-inf')
            for i in range(len(queue)):
                cur = queue.popleft()
                max_val = max(cur.val,max_val)
                if cur.left:
                    queue.append(cur.left)
                if cur.right:
                    queue.append(cur.right)
            res.append(max_val)
        return res