【LeetCode】層數最深葉子節點的和（python）

題目描述

給你一棵二叉樹，請你返回層數最深的葉子節點的和

解題思路

深度搜索優先遍歷二叉樹，先找到葉子節點，然後求和

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:

    def __init__(self):
            self.deepest = 0
            self.sum = 0

    def deepestLeavesSum(self, root: TreeNode) -> int:
        def dfs(node, level):
            if node is None:
                return
            if node.left is None and node.right is None:
                if self.deepest < level:
                    self.sum = node.val
                    self.deepest = level
                elif self.deepest == level:
                    self.sum += node.val

            dfs(node.left, level + 1)
            dfs(node.right, level + 1)

        dfs(root, 0)
        return self.sum