using System;

using System.Text.RegularExpressions;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    static string SplitRegex(string x)

    {

        return Regex.Split(x, "([0-9]+)")[1];

    }

​

    private static int CompareContractNumbers(string x, string y)

    {

        int compareresult = 0;

        int leftconvertresult = 0;

        int rightconvertresult = 0;

        bool leftcanconvertflag = Int32.TryParse(x, out leftconvertresult);

        bool rightcanconvertflag = Int32.TryParse(y, out rightconvertresult);

        if (leftcanconvertflag && !rightcanconvertflag)

        {

            compareresult = -1;

        }

​

        if (!leftcanconvertflag && rightcanconvertflag)

        {

            compareresult = 1;

        }

​

        if (leftcanconvertflag && rightcanconvertflag)

        {

            if (leftconvertresult > rightconvertresult)

            {

                compareresult = 1;

            }

​

            if (leftconvertresult == rightconvertresult)

            {

                compareresult = 0;

            }

​

            if (leftconvertresult < rightconvertresult)

            {

                compareresult = -1;

            }

        }

​

        if (!leftcanconvertflag && !rightcanconvertflag)

        {

            compareresult = CompareString(x, y);

        }

​

        return compareresult;

    }

​

    private static int CompareString(string x, string y)

    {

        var pairs = x.Zip(y, (a, b) => new

        {

        x = a, y = b

        }

​

        );

        foreach (var pair in pairs)

        {

            int value = pair.x.CompareTo(pair.y);

            if (value != 0)

                return value;

        }

​

        return y.Length.CompareTo(x.Length);

    }

​

    public static void Main()

    {

        var list = new List<string>{"12065", "10000-a", "10000", "10000b", "544fa", "a"};

        list.Sort((x, y) => CompareContractNumbers(SplitRegex(x), SplitRegex(y)));

        foreach (var item in list)

        {

            Console.WriteLine(item);

        }

    }

}