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129 sum root to leaf numbers

129. Sum Root to Leaf Numbers

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

难度:

Medium

其实递归不难想到,不过我自己做错在细节方面

如果只有单支,每朝下走一层,代表的数字都增加10, 10* 原本的 + 新节点的数字,最终也是用这个来解

class Solution(object):
    def sumNumbers(self, root):
        """
        :type root: TreeNode
        :rtype: int
        """
        return self.calSum(root,0)


    def calSum(self,root,curSum):
        if root == None:
            return 0
        else:
            curSum = curSum * 10 + root.val
            if root.left == None and root.right == None:
                return curSum
            else:
                return self.calSum(root.left, curSum) + self.calSum(root.right, curSum)





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