129. Sum Root to Leaf Numbers

/**
* 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 {
private:
int travel(TreeNode *root,int val)
{
if(root)
{
int levelval=val*10+root->val;
if(!root->left&&!root->right)
{
return levelval;
}
else if(root->left&&root->right)
return travel(root->left,levelval)+travel(root->right,levelval);
else if(root->left)
{
return travel(root->left,levelval);
}
else
return travel(root->right,levelval);
}
else
return 0;
}
public:
int sumNumbers(TreeNode* root) {
return travel(root,0);
}

};