Given the root of a binary tree, return the maximum average value of a subtree of that tree. Answers within 10-5 of the actual answer will be accepted.
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: root = [5,6,1] Output: 6.00000 Explanation: For the node with value = 5 we have an average of (5 + 6 + 1) / 3 = 4. For the node with value = 6 we have an average of 6 / 1 = 6. For the node with value = 1 we have an average of 1 / 1 = 1. So the answer is 6 which is the maximum.
Example 2:
Input: root = [0,null,1] Output: 1.00000
Constraints:
- The number of nodes in the tree is in the range
[1, 104]. 0 <= Node.val <= 105