# [Solved] Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of nodes at level x is maximal.

## Question

Given the `root` of a binary tree, the level of its root is `1`, the level of its children is `2`, and so on.

Return the smallest level `x` such that the sum of all the values of nodes at level `x` is maximal.

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
```

Constraints:

• The number of nodes in the tree is in the range `[1, 104]`.
• `-105 <= Node.val <= 105`

## Python Solution

```# 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: TreeNode) -> int:
if not root:return
q = [root]
l,ml,ms = 1,1,root.val

while q:
s = 0
tempq = []
while q:
x = q.pop()
s+=x.val
if x.left:tempq.append(x.left)
if x.right:tempq.append(x.right)
if s>ms:
ml = l
ms = s
l+=1
q = tempq

return ml```