#1161

Maximum Level Sum of a Binary Tree

pupil · 555 · lc medium +28 · verified · 70% accepted · 4,122 likes · top 78%

⚑ Recursive DFS Traversal ⚑ BFS / Level-Order Traversal

Description

You are given the root of a binary tree where the root is at level 1, its children are at level 2, and so on.

Find and return the smallest level number x whose nodes have the greatest total value sum.

Example 1:

Input: root = [1,7,0,7,-8,null,null]

Output: 2

Explanation:

Level 1 sum = 1.

Level 2 sum = 7 + 0 = 7.

Level 3 sum = 7 + -8 = -1.

So we return the level with the maximum sum which is level 2.

Example 2:

Input: root = [989,null,10250,98693,-89388,null,null,null,-32127]

Output: 2

Code

# 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 maxLevelSum(self, root: Optional[TreeNode]) -> int:

# 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 maxLevelSum(self, root: Optional[TreeNode]) -> int: