using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        string str = "abcadefabba"; // abc, adef, ab,ba

        Dictionary<int, string> dic = new Dictionary<int, string>(); 

        int idx = 0;

        int maxStrLength = 0;

        if (string.IsNullOrWhiteSpace(str))

        {

            //empty string, print 0 and return

            Console.WriteLine(0);

            return;

        }

​

        foreach (char s in str)

        {

            //  Console.WriteLine(s);

            string curr_str = string.Empty;

            if (dic.ContainsKey(idx))

                curr_str = dic[idx];

            if (curr_str == string.Empty)

            {

                dic[idx] = s.ToString();

            }

            else

            {

                if (curr_str.Contains(s.ToString()))

                {

                    idx++;

                    dic[idx] = s.ToString();

                }

                else

                {

                    dic[idx] = curr_str + s.ToString();

                }

            }

        }

​

        foreach (var item in dic)

        {

            Console.WriteLine(item.Value);

            if (item.Value.Length > maxStrLength)

                maxStrLength = item.Value.Length;

        }

​

        Console.WriteLine("max str length is: " + maxStrLength.ToString());

    }

}