Given the root of a binary tree, find the maximum average value of any subtree of that tree.

(A subtree of a tree is any node of that tree plus all its descendants. The average value of a tree is the sum of its values, divided by the number of nodes.)

 

Example 1:

Input: [5,6,1]Output: 6.00000Explanation: For the node with value = 5 we have and average of (5 + 6 + 1) / 3 = 4.For the node with value = 6 we have and average of 6 / 1 = 6.For the node with value = 1 we have and average of 1 / 1 = 1.So the answer is 6 which is the maximum.

 

Note:

1. The number of nodes in the tree is between 1 and 5000.
2. Each node will have a value between 0 and 100000.
3. Answers will be accepted as correct if they are within 10^-5 of the correct answer.

 

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C#

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 public class Solution { 5     List
     
       avgs = new List
      
       (); 6     public double MaximumAverageSubtree(TreeNode root) 7         { 8             int counter = 0; 9             double summer = 0;10             var result = TreeTraverse(root,ref counter,ref summer);11 12             return avgs.Max();13         }14 15         public double? TreeTraverse(TreeNode subTreeRoot,ref int counter,ref double summer)16         {17             if(subTreeRoot == null)18             {19                 return null;20             }21             int leftCounter = 0;22             int rightCounter = 0;23             double leftSummer = 0;24             double rightSummer = 0;25 26             double? leftSum = TreeTraverse(subTreeRoot.left,ref leftCounter,ref leftSummer);27 28             if (false == leftSum.HasValue)29             {30                 leftSum = 0;31             }32             else33                 counter++;34 35             double? rightSum = TreeTraverse(subTreeRoot.right,ref rightCounter,ref rightSummer);36             37             if (false == rightSum.HasValue)38             {39                 rightSum = 0;40             }41             else42                 counter++;43 44             counter = (leftCounter + rightCounter + 1);45             summer = (leftSummer + rightSummer + subTreeRoot.val);46             avgs.Add(summer / counter);47 48             return subTreeRoot.val;49         }50 }