using System;

​

static class TypeFromBase4

{

    const int symbols = 4;

#if DEBUG

    public interface IValue { int Value { get; } }

    struct T0 : IValue { public int Value => 0; }

    struct T1 : IValue { public int Value => 1; }

    struct T2 : IValue { public int Value => 2; }

    struct T3 : IValue { public int Value => 3; }

    struct A<B, C> : IValue

        where B : struct, IValue

            where C : struct, IValue

            {

                public int Value => default(B).Value * symbols + default(C).Value;

            }

​

    public static int Value(Type t)

    {

        return ((IValue)Activator.CreateInstance(t)).Value;

    }

#else

    struct T0 { }

    struct T1 { }

    struct T2 { }

    struct T3 { }

​

    struct A<B, C>

    {

    }

​

    public static int Value(Type t) { return t.GetHashCode(); }

#endif

​

    public static Type Create(int num)

    {

        int digitsNum;

        for (digitsNum = 1; num >= Math.Pow(symbols, digitsNum); digitsNum++) ;

        Span<byte> digits = stackalloc byte[digitsNum];

​

        while (digitsNum-- > 0)

        {

            var digit = (byte)(num % symbols);

            num /= symbols;

            digits[digitsNum] = digit;

        }

​

        var currentType = typeof(T0);

        foreach (var digit in digits)

        {

            var digitType = digit switch

            {

                    0 => typeof(T0),

                    1 => typeof(T1),

                    2 => typeof(T2),

                    3 => typeof(T3),

                    _ => throw new ArgumentOutOfRangeException()

            };

            if (currentType == typeof(T0))

            {

                currentType = digitType;

            }

            else

            {

                currentType = typeof(A<,>).MakeGenericType(currentType, digitType);

            }

        }

​

        return currentType;

    }

}

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(TypeFromBase4.Create(42));

        Console.WriteLine(TypeFromBase4.Create(43));

    }

}