C# 短链思路如何将长id转化为短的

using System;
using System.Collections.Generic;

namespace Base62
{
    
    
    internal class Program
    {
    
    
        static void Main(string[] args)
        {
    
    
            var oldKey = 366767374860158M;
            var res = Decimal2Str(oldKey);
            Console.WriteLine(res);
            var jiemi = Str2Decimal(res);
            Console.WriteLine(jiemi);
            Console.ReadKey();
        }

        private static readonly string Keys = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ~!@#$%^&*()_=-+<>/\\[]{};?.,";//编码,可加一些字符也可以实现72,96等任意进制转换，但是有符号数据不直观，会影响阅读。
        private static readonly int Exponent = Keys.Length;//幂数

        /// <summary>
        /// decimal 转N进制
        /// </summary>
        /// <param name="val"></param>
        /// <returns></returns>
        public static string Decimal2Str(decimal val)
        {
    
    
            Stack<char> rr = new Stack<char>();
            do
            {
    
    
                decimal ys = val % Exponent;
                val /= Exponent;
                rr.Push(Keys[(int)ys]);
                if (val < Exponent)
                {
    
    
                    rr.Push(Keys[(int)val]);
                }
            } while (val >= Exponent);

            var str = string.Empty;
            while (rr.Count > 0)
            {
    
    
                str += rr.Pop();
            }
            return str;
        }

        /// <summary>
        /// N进制字符串转decimal
        /// </summary>
        /// <param name="value">62 encode string</param>
        /// <returns>Return a specified decimal number that decode by 62 string</returns>
        public static decimal Str2Decimal(string value)//bUI6zOLZTrj
        {
    
    
            decimal result = 0;
            for (int i = 0; i < value.Length; i++)
            {
    
    
                int x = value.Length - i - 1;
                result += Keys.IndexOf(value[i]) * Pow(Exponent, x);// Math.Pow(exponent, x);
            }
            return result;
        }

        /// <summary>
        /// 一个数据的N次方
        /// </summary>
        /// <param name="x"></param>
        /// <returns></returns>
        private static decimal Pow(decimal baseNo, decimal x)
        {
    
    
            decimal value = 1;1 will be the result for any number's power 0.任何数的0次方，结果都等于1
            while (x > 0)
            {
    
    
                value = value * baseNo;
                x--;
            }
            return value;
        }
    }
}