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

.

基本题：

int sumNumbers(TreeNode* root)
{
int total=0;
calSum(root,total,0);
return total;
}
void calSum(TreeNode* root,int& tot,int cur)
{
if (!root)
return;
cur=cur*10+root->val;
if (!root->left&&!root->right)
{
tot+=cur;
return;
}
if(root->left)
calSum(root->left,tot,cur);
if(root->right)
calSum(root->right,tot,cur);
}