Sum Root to Leaf Numbers
Desicription
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.
Note: A leaf is a node with no children.
Example:
代码语言：javascript复制Input: [1,2,3]
1
/
2 3
Output: 25
Explanation:
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Therefore, sum = 12 13 = 25.Example 2:
代码语言：javascript复制Input: [4,9,0,5,1]
4
/
9 0
/
5 1
Output: 1026
Explanation:
The root-to-leaf path 4->9->5 represents the number 495.
The root-to-leaf path 4->9->1 represents the number 491.
The root-to-leaf path 4->0 represents the number 40.
Therefore, sum = 495 491 40 = 1026.Solution
代码语言：javascript复制/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int sumNumbers(TreeNode* currentRoot, int currentSum = 0) {
if(currentRoot == NULL)
return 0;
if(currentRoot->left == NULL && currentRoot->right == NULL)
return currentSum * 10 currentRoot->val;
return sumNumbers(currentRoot->left, currentSum * 10 currentRoot->val)
sumNumbers(currentRoot->right, currentSum * 10 currentRoot->val);
}
};
