leetcode257二叉树所有路径

class Solution {
public:
 vector<string> binaryTreePaths(TreeNode* root) {
        vector<string> res;
        if(root == nullptr) return res;
        
        string restemp = to_string(root->val);
        depth_search(root, res, restemp);
        return res;
    }
    void depth_search(TreeNode *root, vector<string> &res, string restemp){
        if(root->left == NULL && root->right == NULL) res.push_back(restemp);
        if(root->left!=NULL) depth_search(root->left, res, restemp + "->" + to_string(root->left->val));
        if(root->right!=NULL) depth_search(root->right, res, restemp + "->" + to_string(root->right->val));
    }
};