Description
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]
Constraints:
- The number of nodes in the tree will be in the range
[0, 104]. -231 <= Node.val <= 231 - 1
Solution
Python3
# 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]:
res = []
def go(node, level):
nonlocal res
if not node: return
if level == len(res):
res.append(node.val)
elif node.val > res[level]:
res[level] = node.val
go(node.left, level + 1)
go(node.right, level + 1)
go(root, 0)
return res