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.
/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public: int dfs(TreeNode * root, int sum){ if(root == NULL) return 0; sum = sum*10 + root->val; if(root->left == NULL && root->right == NULL) return sum; return dfs(root->left,sum) + dfs(root->right,sum); } int sumNumbers(TreeNode * root) { return dfs(root,0); }};