leetcode-508 Most Frequent Subtree Sum

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.

输入输出实例：

input：[5, 2, -3]

output: [2, -3, 4]

代码：

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def getData(self, root):
        if root == None:
            return 0
        else:
            root.val = root.val + self.getData(root.left) + self.getData(root.right)
            if root.val in self.dic:
                self.dic[root.val] += 1
            else:
                self.dic[root.val] = 1
            return root.val  
        
    def findFrequentTreeSum(self, root: TreeNode) -> List[int]:
        if root == None:return []
        self.dic = {}
        self.getData(root)
        data = sorted(self.dic.items(),key = lambda x:x[1], reverse = True)
        
        maxTime = data[0][1]
        result = []
        for i in range(len(data)):
            if maxTime == data[i][1]:
                result.append(data[i][0])
        return result