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 sumNumbers(TreeNode *root) { vector<int> leaf; int sum = 0; if(root){ leafnum(root, leaf, 0); int len = leaf.size(); for(int i=0;i<len; i++) sum += leaf[i]; return sum; } return NULL; } void leafnum(TreeNode *root, vector<int> &leaf, int crt){ if(root->left == NULL && root->right == NULL){ leaf.push_back(root->val + crt * 10); return; } if(root->left){ leafnum(root->left, leaf, root->val + crt * 10); } if(root->right){ leafnum(root->right, leaf, root->val + crt * 10); } } };
原文：http://www.cnblogs.com/code-swan/p/4140751.html