LeetCode - Binary Tree Level Order Traversal - GoldmanSachs - Easy - C+++

vector<vector<int>> levelOrder(TreeNode* root){
        vector<vector<int>> kow;
        if(root == NULL){
            return kow;
        }
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty()){
            int size = q.size();
            vector<int> kee;
            for(int i = 0; i < size; i++){
                TreeNode* temp = q.front();
                q.pop();
                kee.push_back(temp -> val);
                if(temp -> left){
                    q.push(temp -> left);
                }
                if(temp -> right){
                    q.push(temp -> right);
                }
            }
            kow.push_back(kee);
        }
        return kow;
    }