Most Frequent Subtree Sum
Given the root of a binary tree, return the most frequent subtree sum. If there is a tie, return all the values with the highest frequency in any order.
The subtree sum of a node is defined as the sum of all the node values formed by the subtree rooted at that node, including the node itself.
Example 1
5
/ \
2 -3Input
root = [5,2,-3]Output
[2,-3,4]The subtree sums are 2, -3, and 4, and all occur once, so all are returned.
Example 2
5
/ \
2 -5Input
root = [5,2,-5]Output
[2]The subtree sums are 2, -5, and 2, so 2 is the most frequent subtree sum.
Constraints
- The number of nodes in the tree is in the range
[1, 10^4]. -10^5 <= Node.val <= 10^5
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