using System;

using System.Collections.Generic;

using System.Linq;

​

public static class EnumerableExtensions

{

    public static IEnumerable<T> GetMostFrequent<T>(this IEnumerable<T> inputs, int topXMostFrequent)

    {

        var uniqueGroups = inputs.GroupBy(i => i);

​

        if (uniqueGroups.Count() == topXMostFrequent)

        {

            return uniqueGroups.Select(group => group.Key);

        }

​

        return uniqueGroups.OrderByDescending(i => i.Count())

                           .Take(topXMostFrequent)

                           .Select(group => group.Key);

    }

}

public class Program

{

    public static void Main()

    {

        int[] numbers = { 1, 1, 1, 2, 2, 3 };

        Console.WriteLine("Two most frequent numbers: " + string.Join(", ", numbers.GetMostFrequent(2)));

​

        char[] letters = { 'a', 'a', 'a', 'b', 'b', 'c' };

        Console.WriteLine("Two most frequent letters: " + string.Join(", ", letters.GetMostFrequent(2)));

​

        string[] fruits = { "apple", "apple", "apple", "banana", "banana", "banana", "cherry", "cherry" };

        Console.WriteLine("Two most common fruits: " + string.Join(", ", fruits.GetMostFrequent(2)));

    }

}