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

December LeetCoding Challenge 25

Description

Find Largest Value in Each Tree Row

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

class Solution {
public:
  vector<int> largestValues(TreeNode* root) {
    if(!root) return {};
    vector<int> answer;
    queue<TreeNode *> q;
    q.push(root);
    while(q.size()) {
      int sz = q.size();
      int maximum = INT_MIN;
      for(int _ = 0; _ < sz; ++_) {
        auto current = q.front();
        q.pop();
        maximum = max(maximum, current->val);
        if(current->left) {
          q.push(current->left);
        }
        if(current->right) {
          q.push(current->right);
        }
      }
      answer.push_back(maximum);
    }

    return answer;
  }
};

// Accepted
// 78/78 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 26.8 % of cpp submissions (22.7 MB)