using System;

using System.Collections.Generic;

using System.Linq;

​

public class Task

{

    public Task(string name, params string[] dependencies)

    {

        Name = name;

        Dependencies = dependencies;

    }

​

    /// <summary>

    /// Unique name of the task

    /// </summary>

    public string Name { get; }

​

    /// <summary>

    /// Array of task dependencies

    /// </summary>

    public string[] Dependencies { get; }

​

    public override string ToString()

    {

        return ("- " + Name);

    }

}

​

public class TaskComparer: IComparer<Task>

{

    public virtual int Compare(Task t1, Task t2)

    {

        if (t1.Dependencies.Contains(t2.Name))

            return 1;

        if (t2.Dependencies.Contains(t1.Name))

            return -1;

​

        return 0;

    }

}

​

public class Program

{

    public static void Main()

    {

        // The following array is an example of specific tasks and dependencies between them.

        // For example the following constructor:

        // new Task("task_a", "task_c")

        // means that task_a may be started only after task_c is complete

        var tasks = new[]

        {

            new Task("task_a", "task_c"),

            new Task("task_b", "task_c"),

            new Task("task_c", "task_e"),

            new Task("task_d", "task_a", "task_e"),

            new Task("task_e"),

        };

        var sortedList = tasks.OrderBy(t => t, new TaskComparer()).ToList();

        foreach (Task t in sortedList)

            Console.WriteLine(t.Name);

        Console.WriteLine();

​

        // another set of data

        tasks = new Task[]

        {

            new Task("task_a", "task_b", "task_c"),

            new Task("task_b"),

            new Task("task_c", "task_b"),

        };

        sortedList = tasks.OrderBy(t => t, new TaskComparer()).ToList();

        foreach (Task t in sortedList)

            Console.WriteLine(t.Name);

    }

}