public static void Main(string[] args)
       {
           string input = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW";
           Console.WriteLine(Encode(input));//Outputs: 12W1B12W3B24W1B14W
           Console.WriteLine(Decode(Encode(input)));//Outputs: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW
           Console.ReadLine();
       }
       public static string Encode(string s)
       {
           StringBuilder sb = new StringBuilder();
           int count = 1;
           char current =s[0];
           for(int i = 1; i < s.Length;i++)
           {
               if (current == s[i])
               {
                   count++;
               }
               else
               {
                   sb.AppendFormat("{0}{1}", count, current);
                   count = 1;
                   current = s[i];
               }
           }
           sb.AppendFormat("{0}{1}", count, current);
           return sb.ToString();
       }
       public static string Decode(string s)
       {
           string a = "";
           int count = 0;
           StringBuilder sb = new StringBuilder();
           char current = char.MinValue;
           for(int i = 0; i < s.Length; i++)
           {
               current = s[i];
               if (char.IsDigit(current))
                   a += current;
               else
               {
                   count = int.Parse(a);
                   a = "";
                   for (int j = 0; j < count; j++)
                       sb.Append(current);
               }
           }
           return sb.ToString();
       }