257. Binary Tree Paths

/** * 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 {    void binaryTree(TreeNode *root,vector<int> &cur,vector<vector<int>> &ret)    {        if(root)        {            cur.push_back(root->val);            if(root->left)                binaryTree(root->left,cur,ret);            if(root->right)                binaryTree(root->right,cur,ret);            if(root->left==NULL&&root->right==NULL)                ret.push_back(cur);            cur.pop_back();        }    }public:    vector<string> binaryTreePaths(TreeNode* root) {        vector<int> curi;        vector<vector<int>> reti;        vector<string> ret;        binaryTree(root,curi,reti);        for(int i=0;i<reti.size();i++)        {            string temp;            for(int j=0;j<reti[i].size();j++)            {                if(j<reti[i].size()-1)                {                    temp=temp+to_string(reti[i][j])+"->";                }                else                {                    temp=temp+to_string(reti[i][j]);                }            }            ret.push_back(temp);        }        return ret;    }};