Python | Leetcode Python题解之第508题出现次数最多的子树元素和

题目：

题解：

class Solution:
    def findFrequentTreeSum(self, root: TreeNode) -> List[int]:
        cnt = Counter()
        def dfs(node: TreeNode) -> int:
            if node is None:
                return 0
            sum = node.val + dfs(node.left) + dfs(node.right)
            cnt[sum] += 1
            return sum
        dfs(root)

        maxCnt = max(cnt.values())
        return [s for s, c in cnt.items() if c == maxCnt]