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  • [LeetCode129]Sum Root to Leaf Numbers

    题目:

    Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

    An example is the root-to-leaf path 1->2->3 which represents the number 123.

    Find the total sum of all root-to-leaf numbers.

    For example,

        1
       / 
      2   3
    

    The root-to-leaf path 1->2 represents the number 12.
    The root-to-leaf path 1->3 represents the number 13.

    Return the sum = 12 + 13 = 25.

    分类:Tree DFS 

    代码:

     1 /**
     2  * Definition for a binary tree node.
     3  * struct TreeNode {
     4  *     int val;
     5  *     TreeNode *left;
     6  *     TreeNode *right;
     7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
     8  * };
     9  */
    10 class Solution {
    11 public:
    12     int sumNumbers(TreeNode* root) {
    13         return DFS(root,0);
    14     }
    15     
    16     int DFS(TreeNode* root, int sum)
    17     {
    18         if(!root)
    19             return 0;
    20         int newSum = sum * 10 + root->val;
    21         if(!root->left && !root->right)
    22             return newSum;
    23         return DFS(root->left,newSum) + DFS(root->right,newSum);
    24     }
    25 };

     

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  • 原文地址:https://www.cnblogs.com/zhangbaochong/p/5572686.html
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