Class.cs

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

namespace Zabtkar.Code
{
    class BitSet<T> //where T : IComparable, IComparable<Int32>, IConvertible, IEquatable<Int32>, IFormattable
    {
        Int64 _n;
        public BitSet()
        {
            _n = 0;
        }
        public BitSet(Int64 n)
        {
            _n = n;
        }

        public Int64 Value { get => _n; set => _n = value; }

        public bool Get(int index)
        {
            return (_n & (1 << index)) == 1;
        }
        public void Set(int index, bool value)
        {
            if (value)
                _n |= (1 << index);
            else
                _n &= ~(1 << index);
        }
        public int Length()
        {
            return 0;// sizeof(T) *8;
        }
    }
    public class UniqueIDManager
    {
        private static BitArray ToBitArray(ulong n)
        {
            var bitArray = new BitArray(sizeof(ulong) * 8);
            for (int i = 0; i < sizeof(ulong) * 8; i++)
                bitArray.Set(i, (n & (1UL << i)) != 0);
            return bitArray;
        }
        private static ulong FromBitArray(BitArray bitArray)
        {
            ulong n = 0;
            for (int i = 0; i < bitArray.Length; i++)
            {
                if (bitArray.Get(i))
                    n |= (1UL << i);
                else
                    n &= ~(1UL << i);
            }
            return n;
        }
        private static string ToString(BitArray bitArray)
        {
            string s="";
            for (int i = 0; i < bitArray.Length; i++)
            {
                s = bitArray.Get(i) ? "1" : "0" + s;
            }
            return s;
        }
        public static ulong Encode(ulong n, ref string binary)
        {
            var input = ToBitArray(n);
            var output = new BitArray(sizeof(long) * 8);

            output.Set(11, input.Get(17));
            output.Set(1, input.Get(13));
            output.Set(14, input.Get(1));
            output.Set(10, input.Get(5));
            output.Set(6, input.Get(9));
            output.Set(21, input.Get(11));
            output.Set(20, input.Get(18));
            output.Set(15, input.Get(12));
            output.Set(5, input.Get(3));
            output.Set(12, input.Get(19));
            output.Set(4, input.Get(10));
            output.Set(8, input.Get(21));
            output.Set(22, input.Get(22));
            output.Set(18, input.Get(2));
            output.Set(16, input.Get(20));
            output.Set(7, input.Get(16));
            output.Set(2, input.Get(8));
            output.Set(13, input.Get(14));
            output.Set(9, input.Get(4));
            output.Set(17, input.Get(15));
            output.Set(0, input.Get(7));
            output.Set(3, input.Get(0));
            output.Set(19, input.Get(6));
            output.Set(23, input.Get(23));


            binary = ToString(input);
            return FromBitArray(output);
        }
        public static ulong Decode(ulong n, ref string binary)
        {
            var input = ToBitArray(n);
            var output = new BitArray(sizeof(long) * 8);


            output.Set(17, input.Get(11));
            output.Set(13, input.Get(1));
            output.Set(1, input.Get(14));
            output.Set(5, input.Get(10));
            output.Set(9, input.Get(6));
            output.Set(11, input.Get(21));
            output.Set(18, input.Get(20));
            output.Set(12, input.Get(15));
            output.Set(3, input.Get(5));
            output.Set(19, input.Get(12));
            output.Set(10, input.Get(4));
            output.Set(21, input.Get(8));
            output.Set(22, input.Get(22));
            output.Set(2, input.Get(18));
            output.Set(20, input.Get(16));
            output.Set(16, input.Get(7));
            output.Set(8, input.Get(2));
            output.Set(14, input.Get(13));
            output.Set(4, input.Get(9));
            output.Set(15, input.Get(17));
            output.Set(7, input.Get(0));
            output.Set(0, input.Get(3));
            output.Set(6, input.Get(19));
            output.Set(23, input.Get(23));
            output.Set(24, true);

            binary = ToString(input);
            return FromBitArray(output);
        }
    }
}