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 a binary tree node. * struct TreeNode { * int val; * struct TreeNode *left; * struct TreeNode *right; * }; */ int DFS(struct TreeNode *curNode, int curSum){ int leftSum = 0; int rightSum = 0; curSum += curNode->val; if(curNode->left == NULL && curNode->right == NULL) return curSum; if(curNode->left != NULL) leftSum = DFS(curNode->left, 10 * curSum); if(curNode->right != NULL) rightSum = DFS(curNode->right, 10 * curSum); return leftSum + rightSum; } int sumNumbers(struct TreeNode* root) { // dfs, go deep until to leaf int sum = 0; if(root == NULL) return 0; return DFS(root, 0); }
原文：http://www.cnblogs.com/dylqt/p/5138616.html