using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

using System.Text;

public class Program

{

    public static void Main()

    {

        IList<Tuple<string,string>> data = new List<Tuple<string,string>>()

        {

            Tuple.Create("00000","00001"),

            Tuple.Create("0000001", "0000002"),

            Tuple.Create("99999", "A0000"),

            Tuple.Create("AAAAA", "AAAAB"),

            Tuple.Create("AAAAC", "AAAAD"),

            Tuple.Create("AA900", "AA901"),

            Tuple.Create("CAB37", "CAB38"),

            Tuple.Create("FLA99", "FLB00"),

            Tuple.Create("CAZ99", "CBA00"),

            Tuple.Create("AZZ99", "BAA00")

        };

        foreach(var a in data)

        {

            AlphaNumericId temp = new AlphaNumericId(a.Item1);

            var result = temp.Increment();

            Console.WriteLine("Input value: {0}, Expected result: {1}, Actual result: {2}", a.Item1, a.Item2, result.Id);

        }

    }

}

​

public class AlphaNumericId

{

    public AlphaNumericId(string id)

    {

        Id = id;

    }

​

    private IList<char> _id = new List<char>();

    public string Id

    {

        get

        {

            return Assemble();

        }

        private set

        {

            Disassemble(value);

        }

    }

​

    private void Disassemble(string id)

    {

        foreach (char a in id)

        {

            _id.Insert(0, a);

        }

    }

​

    private string Assemble()

    {

        StringBuilder temp = new StringBuilder();

        for (int i = _id.Count - 1; i >= 0; i--)

        {

            temp.Append(_id[i]);

        }

        return temp.ToString();

    }

​

    public AlphaNumericId Increment()

    {

        bool isReset = false;

        for (int i = 0; i < _id.Count; i++)

        {

            if (i == 0)

            {

                if (Regex.IsMatch(_id[i].ToString(), "\\d")) { _id[i] = char.Parse(Increment(int.Parse(_id[i].ToString())).ToString()); }

                if (Regex.IsMatch(_id[i].ToString(), "\\D")) { _id[i] = Increment(_id[i]); }

                if (_id[i] != '0' && _id[i] != 'Z') { break; }

            }

            else if (i > 0 && i < _id.Count - 1 && ((_id[i - 1] == '0' || _id[i - 1] == 'Z') || isReset))

            {

                if (Regex.IsMatch(_id[i].ToString(), "\\d")) { _id[i] = char.Parse(Increment(int.Parse(_id[i].ToString())).ToString()); }

                if (Regex.IsMatch(_id[i].ToString(), "\\D") && isReset) { _id[i] = Increment(_id[i]); if(_id[i] == 'A') { isReset = false; } continue;}

                if (Regex.IsMatch(_id[i].ToString(), "\\D")) { _id[i] = Increment(_id[i]); if (_id[i] == 'A') { isReset = true; } }

                if (_id[i] != '0' && _id[i] != 'Z' && !isReset) { break; }

            }

            else if (i == _id.Count - 1 && ((_id[i - 1] == '0' || _id[i - 1] == 'Z') || isReset))

            {

                if (Regex.IsMatch(_id[i].ToString(), "[08]")) { _id[i] = char.Parse(Increment(int.Parse(_id[i].ToString())).ToString()); }

                if (Regex.IsMatch(_id[i].ToString(), "[9]")) { _id[i] = 'A'; break; }

                if (Regex.IsMatch(_id[i].ToString(), "[A-Y]")) { _id[i] = Increment(_id[i]); }

            }

        }

        return this;

    }

​

    private char Increment(char ch)

    {

        if (ch == 'Z') { return 'A'; }

        return (++ch);

    }

​

    private int Increment(int ch)

    {

        if (ch == 9) return 0;

        return (++ch);

    }

}