Leetcode006 ZigZag Conversion

 /* 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;
     }
 };