Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

   1
 /   \
2     3
 \
  5

All root-to-leaf paths are:

["1->2->5", "1->3"]

/**
 * 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 {
public:
    vector<string> result;
    vector<string> binaryTreePaths(TreeNode* root) {
        
        if(root == NULL)
            return result;
        getPath(root,to_string(root->val));
        return result;
    }
    
    void getPath(TreeNode* root,string path){
        if(root->left == NULL && root->right == NULL){
            result.push_back(path);
        }
        if(root->left != NULL)
            getPath(root->left,path+"->"+to_string(root->left->val));
        if(root->right != NULL)
            getPath(root->right,path+"->"+to_string(root->right->val));
    }
};