using System;

using System.Text;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var lines_list = new List<string>();

        var wordsArr = new string[]{"alpha", "beta", "gama", "delta", "Epsilon", "Zeta", "Eta", "Theta", "Iota", "kaPPa", "LamBda", "mU", "Nu", "xi", "omicron", "pi", "rHo", "siGma", "Tau", "UpSiLoN", "pHi", "chi", "psi", "omega"};

        var ss = new StringBuilder();

        var rnd = new Random( 12345 );      

        for ( int i = 0; i < 50000; i++ )

        {            

             var words_arr = new List<string>();

             for ( int j = 0; j < rnd.Next(10,20); j++)

             {

                words_arr.Add( wordsArr[ rnd.Next( wordsArr.Length ) ] );            

             }

             var tab_count = rnd.Next( 0, 5 );

             var line = new StringBuilder();

             if ( i % 17 == 0 )

             {

                 line.Append("\t\n");

             }

             else

             {

                if ( i % 33 == 0 )

                 {

                     line.Append("\n");

                 }

                else

                {

                    for ( int k = 0; k < tab_count; k++ ) line.Append("\t");                    

                    foreach( var w in words_arr ) 

                    {

                        line.Append( " " + w );

                    }                   

                }

             }

            var result = line + "\n";

            ss.Append( result );

            lines_list.Add( result );

​

        }

        // Console.Write( ss );

        Console.WriteLine( "Multiline:" );

        var sw = new System.Diagnostics.Stopwatch();

        sw.Start();

        var matches = Regex.Matches( ss.ToString(), "^\\s*(omicron|kappa|upsilon)\\b", RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.Multiline );

        Console.WriteLine( matches.Count );

        Console.WriteLine("Time:" + sw.ElapsedMilliseconds + " ms.");

        Console.WriteLine( "\n\nLine by line:" );

        sw.Restart();

        int count = 0;

        int index = 0;

        foreach( var line in lines_list )

        {

            index++;

            if ( Regex.IsMatch( line, "^\\s*(omicron|kappa|upsilon)\\b", RegexOptions.CultureInvariant | RegexOptions.IgnoreCase | RegexOptions.Compiled ) )

            {

                count++;

            }

        }

        Console.WriteLine( count );

        Console.WriteLine("Time:" + sw.ElapsedMilliseconds + " ms.");

    }

}

/*

space = " "

    nl = "\n"

    tab = "\t"

    tabNl = "\t\n"

    fmt = "%\n"

    wordsArr = #("alpha", "beta", "gama", "delta", "Epsilon", "Zeta", "Eta", "Theta", "Iota", "kaPPa", "LamBda", "mU", "Nu", "xi", "omicron", "pi", "rHo", "siGma", "Tau", "UpSiLoN", "pHi", "chi", "psi", "omega")

    ss = stringStream ""

    for i = 1 to 50000 do

    (

        wordsCnt = random 10 20

        wArr = for j = 1 to wordsCnt collect (wordsArr[random 1 24])

        tabCnt = random 0 5

        str = ""

        if mod i 17 == 0 then

            str = tabNl

        else

        (

            if mod i 33 == 0 then

                str = nl

            else

            (

                for t = 1 to tabCnt do str += tab

                for w in wArr do str += space + w

            )

        )

        format fmt str to:ss

    )

    --)

    strToCheck = toLower (ss as string)

    */