Leetcode 38 Count and Say 传说中的递推

 class Solution {
 public:
     vector<string> vs_;
     Solution(){
         string t("");
         vs_.push_back(t);
         for(int i = ; i< ;++i){
             string t1  = vs_[i - ];
             t = "";
             int cnt = ,j ;

             for(j = ; j < t1.size() - ; ++j){
                 if(t1[j] == t1[j + ]){
                     ++cnt;
                 }
                 else{
                     char s[] ="";
                     sprintf(s,"%d%c",cnt,t1[j]);
                     t += string(s);
                     cnt = ;
                 }
             }
             char s[] ="";
             sprintf(s,"%d%c",cnt,t1[j]);
             t += string(s);
             vs_.push_back(t);
         }
     }
     ~Solution(){
         vs_.clear();
     }

     string countAndSay(int n) {
         return vs_[n-];
     }
 };