LevelOrderAverageBinaryTree

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public List<Double> averageOfLevels(TreeNode root) 
 {
       // List<List<Integer>> answer = new LinkedList<>();
        List<Double> doubAns= new LinkedList<>();
        if(root==null)
            return doubAns;
        Queue<TreeNode> cache = new LinkedList<>();
        cache.add(root);
        while(!cache.isEmpty())
        {
           // List<Integer> currLevel = new LinkedList<>();
            int n = cache.size();
            long sum=0, count=0;
            for(int i =0;i<n;i++)
            {
                TreeNode temp=cache.poll();
                
              //  currLevel.add(temp.val);
                sum+=temp.val;
                count++;
                if(temp.left!=null)
                {cache.add(temp.left);}
                if(temp.right!=null)
                    cache.add(temp.right);
            }
            
          //  answer.add(currLevel);
            doubAns.add((sum*1.0)/count);
        }
        return doubAns;
    }
}