using System;

using System.Collections.Generic;

​

public class Program

{

    /// <summary>

    /// Take these inputs and find all of the different patterns in sourceString of length patternLength and output

    /// all of the patterns that occur more than once and the number of times they occur.

    /// </summary>

    static IEnumerable<KeyValuePair<string, int>> Fiddle(string sourceString, int patternLength)

    {

        if (patternLength <= 0)

        {

            throw new ArgumentException("input patter lenght must be positive", "patternLength");

        }

​

        if (sourceString.Length >= Int32.MaxValue)

        {

            throw new ArgumentException("input string length larger than Substring can handle", "sourceString");

        }

​

        if (patternLength > sourceString.Length)

        {

            throw new ArgumentException("patternLength value larger than input string length", "patternLength");

        }

​

        var myDict = new Dictionary<string, int>();

        for (var index = sourceString.Length - patternLength; index >= 0; --index)

        {

            var pattern = sourceString.Substring(index, patternLength);

            int count;

            if (myDict.TryGetValue(pattern, out count))

            {

                myDict[pattern] = count + 1;

                continue;

            }

​

            myDict.Add(pattern, 1);

        }

​

        foreach (var record in myDict)

        {

            if (record.Value > 1)

                yield return record;

        }

    }

​

    public static void Main()

    {

        // Write a program that these values to find all of the different patterns in "input" of length "patternLength"

        // and output all of the patterns that occur more than once and the number of times they occur.

        // For example, when searching the string "zf3kabxcde224lkzf3mabxc51+crsdtzf3nab=",

        // with a specified pattern length of 3,

        // the method should return the pattern "abx” with an occurrence value of two

        // and “zf3” with an occurrence value of three.

        var result = Fiddle("zf3kabxcde224lkzf3mabxc51+crsdtzf3nab=", 3);

        foreach (var record in result)

        {

            Console.WriteLine(record);

        }

    }

}