using System;

using System.Diagnostics;

using System.Linq;

​

public static class Program

{

    public static void Main()

    {

        int[] array = Enumerable.Range(1, 12).ToArray();

        Console.WriteLine($"Array: {String.Join(", ", array)}");

        int k = 5;

        Console.WriteLine($"Rotate({k})");

        Rotate(array, k);

        Console.WriteLine($"Array: {String.Join(", ", array)}");

        k = -2;

        Console.WriteLine($"Rotate({k})");

        Rotate(array, k);

        Console.WriteLine($"Array: {String.Join(", ", array)}");

    }

​

    /// <summary>

    /// Rotate left for negative k. Rotate right for positive k.

    /// </summary>

    public static void Rotate<T>(T[] array, int k)

    {

        ArgumentNullException.ThrowIfNull(array);

        k = k % array.Length;

        if (k < 0) k += array.Length;

        if (k == 0) return;

        Debug.Assert(k > 0);

        Debug.Assert(k < array.Length);

​

        Array.Reverse(array, 0, array.Length - k);

        Array.Reverse(array, array.Length - k, k);

        Array.Reverse(array);

    }

}

​