1from collections import deque
2
3class TreeNode:
4    def __init__(self, x):
5        self.val = x
6        self.left = None
7        self.right = None
8
9class Solution:
10    def averageOfLevels(self, root):
11        if not root:
12            return []
13        averages = []
14        queue = deque([root])
15        while queue:
16            level_sum, level_count = 0, len(queue)
17            for _ in range(level_count):
18                node = queue.popleft()
19                level_sum += node.val
20                if node.left:
21                    queue.append(node.left)
22                if node.right:
23                    queue.append(node.right)
24            averages.append(level_sum / level_count)
25        return averages
26
27# Example Usage
28if __name__ == "__main__":
29    a = TreeNode(3)
30    b = TreeNode(9)
31    c = TreeNode(20)
32    d = TreeNode(15)
33    e = TreeNode(7)
34    a.left = b
35    a.right = c
36    c.left = d
37    c.right = e
38    
39    solution = Solution()
40    result = solution.averageOfLevels(a)
41    print(result)

using System.Collections.Generic;

public class TreeNode {
    public int val;
    public TreeNode left;
    public TreeNode right;
    public TreeNode(int x) { val = x; }
}

public class Solution {
    public IList<double> AverageOfLevels(TreeNode root) {
        List<long> sums = new List<long>();
        List<int> counts = new List<int>();
        dfs(root, 0, sums, counts);
        List<double> averages = new List<double>();
        for (int i = 0; i < sums.Count; i++) {
            averages.Add((double)sums[i] / counts[i]);
        }
        return averages;
    }
    
    private void dfs(TreeNode node, int level, List<long> sums, List<int> counts) {
        if (node == null) return;
        if (level == sums.Count) {
            sums.Add(node.val);
            counts.Add(1);
        } else {
            sums[level] += node.val;
            counts[level]++;
        }
        dfs(node.left, level + 1, sums, counts);
        dfs(node.right, level + 1, sums, counts);
    }
    
    public static void Main(string[] args) {
        TreeNode a = new TreeNode(3);
        TreeNode b = new TreeNode(9);
        TreeNode c = new TreeNode(20);
        TreeNode d = new TreeNode(15);
        TreeNode e = new TreeNode(7);
        a.left = b;
        a.right = c;
        c.left = d;
        c.right = e;
        
        Solution solution = new Solution();
        IList<double> result = solution.AverageOfLevels(a);
        foreach (double avg in result) {
            Console.Write(avg + " ");
        }
    }
}