515. 在每个树行中找最大值
您需要在二叉树的每一行中找到最大的值。
示例：
输入:
1
/ \
3 2
/ \ \
5 3 9
输出: [1, 3, 9]解法一
bfs
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def largestValues(self, root: TreeNode) -> List[int]:
if not root:
return []
result = []
queue = [root]
while queue:
m = float('-inf')
for i in range(len(queue)):
node = queue.pop(0)
m = max(node.val, m)
if node.left:
queue.append(node.left)
if node.right:
queue.append(node.right)
result.append(m)
return result