// Inspired by this stackoverflow question: https://stackoverflow.com/q/77251327/3094533

​

using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var card = BingoGenerator.CreateCard();

        PrintCard(card);

    }

    private static void PrintCard(int?[][,] card)

    {

        foreach(var table in card)

        {

            for(var i=0;i<table.GetLength(0);i++)

            {

                for(var j=0;j<table.GetLength(1);j++)

                {

                   Console.Write("[{0,2}]", table[i,j].HasValue ? table[i,j].ToString() : "");  

                }

                Console.WriteLine();

            }

            Console.WriteLine();

        }

    }

}

​

​

​

static class BingoGenerator {

​

    private const int rowsPerTable = 3; 

    private const int tablesPerCard = 3;

    private const int numberOfRows = tablesPerCard * rowsPerTable;

    private const int blanksPerRow = 4;

    private const int numbersPerRow = 5;

    private const int numberOfColumns = blanksPerRow + numbersPerRow;

    private static bool[] _rowTemplate = Enumerable

        .Range(0, blanksPerRow)

        .Select(_ => false)

        .Concat(Enumerable.Range(0, numbersPerRow).Select(_ => true))

        .ToArray();

​

    private static Random _rnd = new();

    public static int?[][,] CreateCard()

    {

        var columns = CreateColumns().ToArray();

        var rows = CreateRows();

        return CreateTables(columns, rows);

    }

​

    private static int?[][,] CreateTables(int[][] columns, IEnumerable<bool[]> rows)

    {

        var tables = new int?[tablesPerCard][,];

        for(var i=0;i<tablesPerCard;i++)

        {

            tables[i] = CreateTable(i, columns, rows.Skip(i * tablesPerCard).Take(rowsPerTable));

        }

        return tables;

    }

​

    private static int?[,] CreateTable(int tableNumber, int[][] columns, IEnumerable<bool[]> rows)

    {

        var table = new int?[rowsPerTable, numberOfColumns];

        var j=0;

        foreach(var row in rows)

        {

            for(var i=0;i<numberOfColumns;i++)

            {

                table[j,i] = row[i] ? columns[i][j + (tableNumber * rowsPerTable)] : null;

            }

            j++;

        }

        return table;

    }

​

    private static IEnumerable<bool[]> CreateRows()

        => Enumerable

            .Range(0, numberOfRows)

            .Select(_ => _rowTemplate.OrderBy(r => _rnd.Next()).ToArray());

    private static IEnumerable<int[]> CreateColumns()

        => Enumerable

            .Range(0, numberOfColumns)

            .Select(CreateColumn);

    private static int[] CreateColumn(int columnIndex)

        => Enumerable

            .Range(1 + (10 * columnIndex), numberOfRows)

            .OrderBy(r => _rnd.Next())

            .ToArray();

}

​