Sum Root to Leaf Numbers

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.

dfs.

int ans=0;void dfs(TreeNode *root, int temp){    temp=10*temp+root->val;    if(root->left==NULL && root->right==NULL)        ans+=temp;    if(root->left != NULL)        dfs(root->left,  temp);    if(root->right != NULL)        dfs(root->right,  temp);}int sumNumbers(TreeNode *root){    if(root==NULL)        return 0;    dfs(root,0);    return ans;}