Today I have done leetcode's June LeetCoding Challenge with cpp.

June LeetCoding Challenge 15

Description

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

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int maxLevelSum(TreeNode* root) {
    int answer;
    int sum = INT_MIN;
    queue<TreeNode*> q;
    q.push(root);
    int level = 0;
    while(q.size()) {
      int sz = q.size();
      int currentSum = 0;
      level += 1;
      for(int _ = 0; _ < sz; ++_) {
        auto current = q.front();
        q.pop();
        currentSum += current->val;
        if(current->left) q.push(current->left);
        if(current->right) q.push(current->right);
      }
      if(currentSum > sum) {
        sum = currentSum;
        answer = level;
      }
    }
    return answer;
  }
};

// Accepted
// 40/40 cases passed (184 ms)
// Your runtime beats 95.85 % of cpp submissions
// Your memory usage beats 13.54 % of cpp submissions (107.5 MB)