### LeetCode Challenge #1161. Maximum Level Sum of a Binary Tree

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`
##### Video Solution
###### C++ Solution
```				```
class Solution {
public:
int bfs(TreeNode* root)
{
queue<TreeNode*> q;

int n,sum=0,level=1,maxm=INT_MIN,maxLevel;
q.push(root);
while(!q.empty()){
n = q.size();
sum = 0;
while(n--){
TreeNode* node = q.front();q.pop();
sum += node->val;
if(node->left)q.push(node->left);
if(node->right)q.push(node->right);
}
if(sum>maxm){
maxm = sum;
maxLevel = level;
}
level++;
}
return maxLevel;
}

int maxLevelSum(TreeNode* root) {

return bfs(root);

}
};
```
```