FB 129. Sum Root to Leaf Numbers

https://leetcode.com/problems/sum-root-to-leaf-numbers/

DFS 解法

class Solution:
    def sumNumbers(self, root: TreeNode) -> int:
        result = []
        def dfs(node,path, result):
            if node == None:
                return
            if node.left == None and node.right == None:
                result.append(path+str(node.val))
                return
            dfs(node.left, path+str(node.val),result)
            dfs(node.right,path+str(node.val),result)
        dfs(root,"",result)
        return sum([int(i) for i in result])