link关于课程表的问题要求每天都有自修课，请问在如下代码的基础上怎么修改？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
string[] courses = { "体育课", "体育课", "美术课", "音乐课", "劳动课", "语文课", "数学课", "英语课"};
var result = Enumerable.Range(0, 5).Select(_ => Enumerable.Range(0, 6).Select(__ => "").ToArray()).ToArray();
while (!result.All(x => x.Contains("语文课") && x.Contains("数学课") && x.Contains("英语课")))
{
var rndseq = Enumerable.Range(0, 30).OrderBy(_ => Guid.NewGuid()).Zip(courses, (x, y) => new { x, y }).ToArray();
for (int i = 0; i < 5; i++)
{
int pos = 0;
string[] cs = { "语文课", "数学课", "英语课" };
for (int j = 0; j < 6; j++)
{
if (rndseq.Any(x => x.x == i * 6 + j))
result[i][j] = rndseq.First(x => x.x == i * 6 + j).y;
else
result[i][j] = (pos++ < 3) ? cs[pos - 1] : "自修课";
}
}
}
result = result.Select(x => x.OrderBy(y => y == "自修课" ? 1 : 0).ThenBy(_ => Guid.NewGuid()).GroupBy(y => y).SelectMany(y => y).ToArray()).ToArray();
for (int j = 0; j < 6; j++)
{
for (int i = 0; i < 5; i++)
{
Console.Write(result[i][j] + "\t");
}
Console.WriteLine();
}
}
}
}

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] courses = { "体育课", "体育课", "美术课", "音乐课", "劳动课", "语文课", "数学课", "英语课"};
            var result = Enumerable.Range(0, 5).Select(_ => Enumerable.Range(0, 6).Select(__ => "").ToArray()).ToArray();
            while (!result.All(x => x.Contains("语文课") && x.Contains("数学课") && x.Contains("英语课") && x.Contains("自修课")))
            {
                var rndseq = Enumerable.Range(0, 30).OrderBy(_ => Guid.NewGuid()).Zip(courses, (x, y) => new { x, y }).ToArray();
                for (int i = 0; i < 5; i++)
                {
                    int pos = 0;
                    string[] cs = { "语文课", "数学课", "英语课" };
                    for (int j = 0; j < 6; j++)
                    {
                        if (rndseq.Any(x => x.x == i * 6 + j))
                            result[i][j] = rndseq.First(x => x.x == i * 6 + j).y;
                        else
                            result[i][j] = (pos++ < 3) ? cs[pos - 1] : "自修课";
                    }
                }
            }
            result = result.Select(x => x.OrderBy(y => y == "自修课" ? 1 : 0).ThenBy(_ => Guid.NewGuid()).GroupBy(y => y).SelectMany(y => y).ToArray()).ToArray();
            for (int j = 0; j < 6; j++)
            {
                for (int i = 0; i < 5; i++)
                {
                    Console.Write(result[i][j] + "\t");
                }
                Console.WriteLine();
            }
        }
    }
}

数学课 英语课 音乐课 语文课 语文课
数学课 英语课 美术课 体育课 英语课
劳动课 语文课 英语课 体育课 数学课
语文课 语文课 数学课 英语课 自修课
英语课 数学课 语文课 数学课 自修课
自修课 自修课 自修课 自修课 自修课
Press any key to continue . . .

while (!result.All(x => x.Contains("语文课") && x.Contains("数学课") && x.Contains("英语课") && x.Contains("自修课")))