# ---
# title: 508. Most Frequent Subtree Sum
# id: problem508
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Hash Table, Tree
# link: <https://leetcode.com/problems/most-frequent-subtree-sum/description/>
# hidden: true
# ---
# 
# Given the root of a tree, you are asked to find the most frequent subtree sum.
# 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). So what is the
# most frequent subtree sum value? If there is a tie, return all the values with
# the highest frequency in any order.
# 
# **Examples 1**  
# Input:
# 
#     
#     
#       5
#      /  \
#     2   -3
#     
# 
# return [2, -3, 4], since all the values happen only once, return all of them
# in any order.
# 
# **Examples 2**  
# Input:
# 
#     
#     
#       5
#      /  \
#     2   -5
#     
# 
# return [2], since 2 happens twice, however -5 only occur once.
# 
# **Note:** You may assume the sum of values in any subtree is in the range of
# 32-bit signed integer.
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
