/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:

    int sumRootToLeaf(TreeNode* root) {

        if(root==nullptr){
            return 0;
        }

        if(root->left==nullptr&&root->right==nullptr){
            return root->val;
        }
        if(root->left==nullptr){
            return root->val+2*sumRootToLeaf(root->right);
        }
        if(root->right==nullptr){
            return root->val+2*sumRootToLeaf(root->left);
        }

        return root->val+2*sumRootToLeaf(root->left)+2*sumRootToLeaf(root->right);
    }
};