LeetCode 129. Sum Root to Leaf Numbers

题目

思路

递归，计算出所有从根节点到叶子节点的数字，保存起来，最后相加。

代码

# 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.num_list = []
    def findNums(self, root, num):
        if not root: return
        if not root.left and not root.right:
            self.num_list.append(num * 10 + root.val)
        else:
            if root.left:
                self.findNums(root.left, num * 10 + root.val)
            if root.right:
                self.findNums(root.right, num * 10 + root.val)
    def sumNumbers(self, root):
        """ :type root: TreeNode :rtype: int """
        self.findNums(root, 0)
        return sum(self.num_list)