LeetCode OJ：Restore IP Addresses（存储IP地址）

Given a string containing only digits, restore it by returning all possible valid IP address combinations.

For example:
Given "25525511135",

return ["255.255.11.135", "255.255.111.35"]. (Order does not matter)

典型的dfs，但是要点是注意什么才是真的ip地址，代码如下：

 class Solution {
 public:
     vector<string> restoreIpAddresses(string s) {
         if (s.size() > ) return ret;
         dfs(s, , );
         return ret;
     }

     bool check(string &s)
     {
         if (s.size() == )
             return "" <= s && s <= "";
         else if (s.size() == )
             return "" <= s && s <= "";
         else if (s.size() == )
             return "" <= s && s <= "";
         else
             return false;
     }

     void dfs(const string & s, int start, int nth)
     {
         if (nth ==  && start != s.size())
             return;
         else if (nth ==  && start == s.size()){
             string tmp = "";
             for (int i = ; i < ; ++i){
                 tmp += tmpRes[i];
                 tmp += ".";
             }
             tmp += tmpRes[];    //为了凑格式
             ret.push_back(tmp);
         }
         else
             for (int i = ; i < ; ++i){
                 if(start + i <= s.size()){
                     string tmp = s.substr(start, i);
                     if(check(tmp)){
                         tmpRes.push_back(tmp);
                         dfs(s, start + i, nth + );
                         tmpRes.pop_back();
                     }
                 }
             }
     }

 private:
     vector<string> tmpRes;
     vector<string> ret;
 };

写的有点乱了 ，见谅见谅