using System;

using System.Drawing;

using System.Drawing.Imaging;

using System.Text;

using System.Runtime.InteropServices;

using System.IO;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Reverse("ABCD"));

        Console.WriteLine(Reverse("一二三四"));

​

​

    }

    static string Reverse(string s)

    {

        byte[] b = Encoding.UTF32.GetBytes(s);

        PixelFormat fmt = PixelFormat.Format32bppPArgb;

        using(Bitmap bmp = new Bitmap(1, b.Length / 4, fmt))

        {

            var bmpData = bmp.LockBits(new Rectangle(Point.Empty, bmp.Size), ImageLockMode.ReadWrite, fmt);

            Marshal.Copy(b, 0, bmpData.Scan0, b.Length);

            bmp.UnlockBits(bmpData);

​

            using (MemoryStream ms = new MemoryStream())

            {

                bmp.Save(ms, ImageFormat.Bmp);

                var bb = ms.ToArray();

​

                return Encoding.UTF32.GetString(bb,54,bb.Length-54);

            }

        }   

    }

}