Would this be considered constant space? I am not using any local variables inside the recursion.

```
class Solution {
public:
void findSum(TreeNode *root, int &cur_sum, int &final_sum)
{
if(root == NULL)
return;
cur_sum= cur_sum*10 + root->val;
if(root->left==NULL && root->right == NULL)
{
final_sum+= cur_sum;
cur_sum = (cur_sum-root->val)/10;
return;
}
if(root->left) findSum(root->left, cur_sum, final_sum);
if(root->right) findSum(root->right, cur_sum, final_sum);
cur_sum = (cur_sum - root->val)/10;
}
int sumNumbers(TreeNode* root) {
int cur_sum = 0;
int final_sum = 0;
findSum(root, cur_sum, final_sum);
return final_sum;
}
};
```