public class Program
    {
        static List<string[]> s_result = new List<string[]>();
        static Stack<string> s_current = new Stack<string>();

        static void Main(string[] args)
        {
            string s = "25482";
            int groupCount = 3;

            Part(s, groupCount);

            foreach (var r in s_result)
            {
                Console.WriteLine(string.Join("|", r));
            }

            Console.Read();
        }

        static void Part(string s, int groupCount)
        {
            if (groupCount == 1)
            {
                s_current.Push(s);
                s_result.Add(s_current.Reverse().ToArray());
                s_current.Pop();
                return;
            }

            for (int p = 1; p <= s.Length - groupCount + 1; p++)
            {
                s_current.Push(s.Substring(0, p));
                Part(s.Substring(p, s.Length - p), groupCount - 1);
                s_current.Pop();
            }
        }

    }