DataGrids

void Main() { var input = "1113222113"; // part 1 var value = input; for (var counter = 0; counter < 40; counter++) value = LookAndSay(value); value.Length.Dump(); // part 2 value = input; for (var counter = 0; counter < 50; counter++) value = LookAndSay(value); value.Length.Dump(); } string LookAndSay(string i) { var ret = new StringBuilder(); int pos = 0; while (pos < i.Length) { var counter = 0; var current = i[pos]; while ((pos+counter) < i.Length && i[pos+counter] == current) counter++; ret.AppendFormat("{0}{1}", counter, current); pos += counter; } return ret.ToString(); }