Recursion1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
double max = Integer.MIN_VALUE;
// double[]: sum, count
private double[] util(TreeNode root){
if(root==null) return new double[]{0,0};
double[] l=util(root.left),r=util(root.right);
double sum=root.val+l[0]+r[0];
double count=l[1]+r[1]+1;
double avg=sum/count;
if(avg>max){
max=avg;
}
return new double[]{sum,count};
}
public double maximumAverageSubtree(TreeNode root) {
util(root);
return max;
}
}