using System;

using System.Linq;

using System.Threading;

​

class Program

{

    static void Main(string[] args)

    {

        int sizeThread = 20;

        int sizeMain = 20;

​

        //int[] inputs = new int[] { 999999999, 888888888, 998990996, 667889776, 955755655, 994995996, 911822733 };

        long[] inputs = new long[] { 2101000000, 1800000000, 1501000000, 2110000000 };

​

        var startTime = DateTime.Now;

        Console.WriteLine($"Using single thread. Started: {startTime.ToLongTimeString()}");

​

        foreach (var input in inputs)

            Sum(input);

​

        var finishTime = DateTime.Now;

        Console.WriteLine($" Single thread - Finished at {finishTime.ToLongTimeString()}. Total time consumed (in sec): {(finishTime - startTime).TotalSeconds}");

​

        startTime = DateTime.Now;

        Console.WriteLine($"Using multi threads. Started: {startTime.ToLongTimeString()}");

​

        foreach (var input in inputs)

        {

            // создаем новый поток

            Thread myThread = new Thread(() => Sum(input));

            myThread.Start(); // запускаем поток

        }

​

        Console.WriteLine($" Multi threads - Total time consumed (in sec): {(DateTime.Now - startTime).TotalSeconds}");

​

        Console.ReadLine();

    }

​

    public static void Sum(long input)

    {

        Console.WriteLine($"-------  input {input}. Started: {DateTime.Now.ToLongTimeString()}");

        var startTime = DateTime.Now;

        long result = 1;

        for (int i = 1; i <= input; i++)

            result += i;

​

        Console.WriteLine($"--------  Sum of {input} equals {result: # ###}, finished at {DateTime.Now.ToLongTimeString()}. Time consumed (in sec): {(DateTime.Now - startTime).TotalSeconds}");

    }

​

    public static void Count(int size)

    {

        for (int i = 1; i < size; i++)

        {

            Console.WriteLine("Второй поток:");

            Console.WriteLine(i * i);

            Thread.Sleep(400);

        }

    }

}