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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); }
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原文地址:http://www.cnblogs.com/dylqt/p/5138616.html