using System;

using System.Linq;

​

namespace ConsoleApplication1

{

    public class Program

    {

        public static void Main()

        {

            var collection1 = new[] {1, 1, 3, 4, 5};

            var collection2 = new[] {1, 3, 1, 4, 5};

​

            var result = IsAllContains(collection1, collection2);

            Console.WriteLine(result);

        }

​

        public static bool IsAllContains(int[] collection1, int[] collection2)

        {

            var buffer = collection2.ToList();

​

            foreach (var item in collection1)

            {

                if (buffer.Contains(item))

                {

                    buffer.Remove(item);

                }

                else

                {

                    return false;

                }

            }

            return true;

        }

    }

}

​