leetcode 257.二叉树的所有路径

/**
 * 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:
    void getPath(TreeNode* root,vector<string> &result,vector<int> &path){
        path.push_back(root->val);
        if(root->left==NULL&&root->right==NULL){
            string sPath;
            for(int i=0;i<path.size()-1;i++){
                sPath+=to_string(path[i]);
                sPath+="->";
            }
            sPath+=to_string(path[path.size()-1]);
            result.push_back(sPath);
            return;
        }
        if(root->left){
            getPath(root->left,result,path);
            path.pop_back();

        }
        if(root->right){
            getPath(root->right,result,path);
            path.pop_back();
        }
    }
    vector<string> binaryTreePaths(TreeNode* root) {
        vector<string> result;
        vector<int> path;
        if(root==NULL) return result;
        getPath(root,result,path);
        return result;
    }
};