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”]

方法： 注意to_string的用法。

/** * 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 {private:    void find(TreeNode* root,vector<string> &res, string cur_path){        if(!root->left && !root->right){            res.push_back(cur_path+to_string(root->val));            cur_path.erase(cur_path.size());            return;        }        if(root->left)            find(root->left,res,cur_path+to_string(root->val)+"->");        if(root->right)            find(root->right,res,cur_path+to_string(root->val)+"->");    }public:    vector<string> binaryTreePaths(TreeNode* root) {        vector<string> res;        if(!root)            return res;        find(root,res,"");        return res;    }};