Найти количество вхождений элемента в массив

int[] temp = new int[] { 11, 11, 11, 12, 13, 13, 14, 14, 15 };
Console.WriteLine(temp.Distinct().Count());

 oneDay[i].subject = list[randNumber].subject;
 
 
                if (oneDay.Select(a => a.subject).Distinct().Count() <= 3)
                {
                    list[randNumber].countHour++;
                }

MessageBox.Show(oneDay.Select(a => a.subject).Distinct().Count().ToString());

static void Main(string[] args)
        {
            int[] temp = new int[] { 11, 11, 11, 12, 13, 13, 14, 14, 15 };
            temp.GroupBy(i => i).ToList().ForEach(v => { Console.WriteLine(v.Key + " " + v.Count()); });
            Console.WriteLine();
            Console.ReadKey();
        }

using System;
using System.Collections.Generic;
using System.Linq;
 
namespace ConsoleApplication6
{
    class Program
    {
        static void Main(string[] args)
        {
            
            int[] temp = new int[] { 11, 11, 11, 12, 13, 13, 14, 14, 15, 11, 13, 13, 14, 1, 15, 11 };
 
            IEnumerable<dynamic> result = from c in temp
                group c by c
                into grpC
                where grpC.Count() > 3
                select new {key = grpC.Key, count = grpC.Count()};
 
            //or this
            result = temp.GroupBy(c => c).Where(grp => grp.Count() > 3).Select(grp => new { Key = grp.Key, Count = grp.Count() });
 
            foreach (dynamic item in result)
            {
                Console.WriteLine(string.Format("key: {0}, count: {1}", item.Key, item.Count));
            }
            Console.ReadLine();
 
        }
    }
}