/* simple simulation algorithm

  * we cann`t make sure the size of the string,

  * so it had better to storage in vector.

  * show[] to buffer the new order of the string

  */

 class Solution {

 public:

     string convert(string s, int numRows) {

      string result;

      vector<char> show[numRows];

      for(int index=;index<s.size();)   //divide into two parts

      {

          for(int i=;i<numRows;i++)     //simple row full storage

          {

              show[i].push_back(s[index++]);

              if(index==s.size())break;

          }

          for(int i=;i<=numRows-;i++)  //middle row only only one char storaged

          {

              for(int j=numRows-;j>=;j--)

              {

                  if(i+j==numRows-)show[j].push_back(s[index++]);

                  if(index==s.size())break;

              }

              if(index==s.size())break;

          }

      }

      for(int i=;i<numRows;i++)

      {

          for(int j=;j<show[i].size();j++)result+=show[i][j];

      }

      return result;

     }

 };