Leetcode题 257. 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"]

代码如下：

/** * 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:    //按照容易自己习惯的数据结构来存储路径，最后做一个转换    void findPath(TreeNode* t,vector<int>& temp, vector<vector<int> >& record)    {        temp.push_back(t->val);    if(t->left!=NULL) findPath(t->left, temp, record);    if(t->right!=NULL) findPath(t->right, temp, record);    //到达叶子节点，就记录路径    if(t->left==NULL && t->right==NULL)    {        record.push_back(temp);        temp.erase(temp.end()-1);        return ;    }    //中间节点返回    temp.erase(temp.end()-1);    return;    }    vector<string> binaryTreePaths(TreeNode* root) {        vector<vector<int>> record;        vector<string> srecord;    if(root==NULL) return srecord;    vector<int> temp;    //找到所有的路    findPath(root,temp,record);    //把所有的路按照题目要求存储    string stemp;    for(int i=0;i<record.size();i++)    {        stringstream ss;        for(int j=0;j<record[i].size();j++)        {            ss<<record[i][j]<<"->";        }        stemp.clear();        stemp=ss.str();        //去掉最后的"->"        stemp.pop_back();        stemp.pop_back();        srecord.push_back(stemp);    }    return srecord;    }};