// Krishna's C# program to count occurences for Frozen Mountain

using System;

using System.Collections;

public class KP {

​

    static void countFreq(int patlen, String txt) {

        int N =  txt.Length;

        String patStr;

        Hashtable patHash = new Hashtable{};

        for (int i=0; i <N-patlen-1; i++)

        {

            patStr =  txt.Substring(i,patlen);

            for (int j=0; j <N-patlen+1; j++)

            {

                if (patStr.ToString() == txt.Substring(j,patlen))

                {

                    if (patHash.ContainsKey(patStr))

                        {patHash[patStr] =  Convert.ToInt32(patHash[patStr]) +1;}

                        else

                        {patHash.Add(patStr,1);}

                        }

                    }

                }

                foreach (string key in patHash.Keys)

                {

                    if (Convert.ToInt32(patHash[key]) >= 2)

                    {Console.WriteLine("(0):(1)",key, patHash[key]);}

                }

    }

    /* Driver program to test above function */

    static public void Main() {

        Console.WriteLine("Enter Pattern");

        String txt =Console.ReadLine();

        Console.WriteLine("Enter Pattern Length");

        int patlen = Convert.ToInt32(Console.ReadLine());

        countFreq(patlen, txt);

    }

}

​