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,
代码语言：javascript复制 1
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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.
求根到叶表示的所有数的和。
DFS
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:
void dfs(TreeNode* root,int &res,int now)
{
if(!root) return ;
if(!root->left && !root->right) res =now*10 root->val;
dfs(root->left,res,now*10 root->val);
dfs(root->right,res,now*10 root->val);
}
int sumNumbers(TreeNode* root) {
int res=0;
dfs(root,res,0);
return res;
}
};
