在 C# 中以预设的时间表运行四个任务

Question

I have an exercise in asynchronous programming like this: There are 4 Tasks: Task1 , Task2 , Task3 , Task4 . Task1 and Task2 run in parallel. Task3 is only run when either Task1 or Task2 completes. Task4 runs when all 3 previous tasks must be completed. This is how I do it, but my teacher asked me not to separate the function to handle Task.WaitAny() (in the picture is the waitAny() function), and not to use async in ContinueWith . Can someone help me?
Screenshot with code .

static async Task<int> waitAny()
{
    return Task.WaitAny(runTask1(), runTask2());
}

static void Main(string[] args)
{
    waitAny().ContinueWith( 
    async (_taskToContinue) => 
    {
        await runTask3();

        Task.WaitAll(runTask1(), runTask2(), runTask3());

        await runTask4();

    });

    Console.ReadKey();
}

Answer 1

Would do it like this then.

    static void Main(string[] args)
    {
        var task1 = runTask1();
        var task2 = runTask2();

        Task.WhenAny(task1, task2).ContinueWith(task =>
        {
            var task3 = runTask3();

            Task.WaitAll(task1, task2, task3);

            var task4 = runTask4();
            task4.Wait();
        });
    }