using System;

using System.Collections.Concurrent;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

​

namespace FirstTask

{

    public static class Program

    {

        public static void Main(string[] args)

        {

​

            //FirstTry().Wait();

​

            SecondTry().Wait();

        }

​

        public static async Task FirstTry()

        {

            var variants = Enumerable.Range(1, 20).ToList();

            // first try

            var tasks = variants.ConvertAll(async v => await LongProcedureTrueIfSuccess(v));

            var completed = await Task.WhenAny(tasks);

​

            var result = (await completed) ? "Good" : "Bad";

            Console.WriteLine("Result is " + result);

        }

        public static async Task SecondTry()

        {

            var variants = Enumerable.Range(1, 20).ToList();

            CancellationTokenSource cts = new CancellationTokenSource();

            ConcurrentBag<bool> bag = new ConcurrentBag<bool>();

            Parallel.ForEach(variants,  (v,state) =>

            {

                var r =  LongProcedureTrueIfSuccess(v).Result;

                if (r)

                {

                    bag.Add(r);

                    state.Stop();

                }

            });

            var result = (bag.FirstOrDefault()) ? "Good" : "Bad";

            Console.WriteLine("Result is " + result);

        }

​

        public static async Task<bool> LongProcedureTrueIfSuccess(int i)

        {

            await Task.Delay(1000); //Processing

            Console.WriteLine("We know result");

            if (i == 5)

                return true;

            return false;

        }

    }

}