using System;

​

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

            DateTime dStart = DateTime.Now;

            int[] array1 = { 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11

                           , 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11,

                            7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11, 1, 2, 3, 7, 8, 9, 10, 11};

            int[] array2 = { 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4

                            , 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4

                            , 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4

                            , 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4, 4, 2, 3, 4, 2, 3, 4, 2, 3, 4};

​

            var intersect = array1.Intersect(array2);

​

            foreach (int value in intersect)

            {

                Console.WriteLine(value);

            }

            DateTime dEnd = DateTime.Now;

            Console.WriteLine("intersect : " + (dEnd - dStart).TotalMilliseconds);

​

​

            dStart = DateTime.Now;

            List<int> distinct = new List<int>();

            foreach (int i in array1)

            {

                if (array2.Contains(i))

                {

                    if (!distinct.Contains(i))

                    {

                        Console.WriteLine(i);

                        distinct.Add(i);

                    }

                }

            }

            dEnd = DateTime.Now;

            Console.WriteLine("loop : " + (dEnd - dStart).TotalMilliseconds);

    }

}