Given the <code>root</code> of a binary tree, return <em>the average value of the nodes on each level in the form of an array</em>. Answers within <code>10<sup>-5</sup></code> of the actual answer will be accepted.
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/03/09/avg1-tree.jpg" style="width: 277px; height: 302px;" />
<pre>
<strong>Input:</strong> root = [3,9,20,null,null,15,7]
<strong>Output:</strong> [3.00000,14.50000,11.00000]
Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and on level 2 is 11.
Hence return [3, 14.5, 11].
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/03/09/avg2-tree.jpg" style="width: 292px; height: 302px;" />
<pre>
<strong>Input:</strong> root = [3,9,20,15,7]
<strong>Output:</strong> [3.00000,14.50000,11.00000]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 10<sup>4</sup>]</code>.</li>
	<li><code>-2<sup>31</sup> &lt;= Node.val &lt;= 2<sup>31</sup> - 1</code></li>
</ul>

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
// typedef TreeNode node;
// class Solution {
// public:
//     vector<double> averageOfLevels(TreeNode* root) {
//         queue<node*> q;vector<double> v;
//         if(!root) return {};
//         q.push(root);
//         node* curr;int size; double sum,n;
//         while(!q.empty()){
//             size=q.size();
//             sum=0;n=0;
//             while(size--){
//                 curr=q.front();q.pop();
//                 if(curr->left){q.push(curr->left);curr->left=NULL;}
//                 if(curr->right){q.push(curr->right);curr->right=NULL;}
//                 sum+=curr->val;n++;
//             }
//             v.push_back(sum/n);
//         }
//         return v;
//     }
// };


class Solution {
public:
    vector<double> averageOfLevels(TreeNode* root) {
        
        ios_base::sync_with_stdio(false);
	    cin.tie(nullptr);
        cout.tie(nullptr);

       
        vector<double> db;
        queue<TreeNode*> tr;

        tr.push(root);
        int n, size;
        double sum;
        TreeNode *tk;

        while(!tr.empty()){

         size=n=tr.size();
         sum=0;
         while(size--){           
            tk= tr.front(); tr.pop();
            sum+= tk->val;
            if(tk->left)  {tr.push(tk->left);     }          
            if(tk->right) { tr.push(tk->right);     }            
        }
    
       db.push_back(sum/n);

     }
     
     
     return db;

    }
};
22800