using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

​

/* Don't change anything here.

 * Do not add any other imports. You need to write

 * this program using only these libraries 

 */

​

namespace ProgramNamespace

{

    /* You may add helper classes here if necessary */

​

    public class Program

    {

        public class AppData

        {

            public string appName;

            public string APIName;

            public string APIVersion;

        }

        public static List<String> processData(

                                        IEnumerable<string> lines)

        {

            /* 

             * Do not make any changes outside this method.

             *

             * Modify this method to process `array` as indicated

             * in the question. At the end, return the size of the

             * array. 

             *

             * Do not print anything in this method

             *

             * Submit this entire program (not just this function)

             * as your answer

             */

            AppData  appObj= new AppData();

            List<AppData> appDetailsList= new List<AppData>();

            foreach (string appData in lines)

            {

                string[] tempString =appData.Split(',');

                appObj.appName=tempString[0];

                appObj.APIName=tempString[1];

                appObj.APIVersion=tempString[2];                

                appDetailsList.Add(appObj);

            }

            List<string> distinctAPIs= appDetailsList.Select(o => o.APIName).Distinct().ToList();

            List<String> retVal = new List<String>();

            foreach (string apiVal in distinctAPIs)

            {       

                var newList=(from order in appDetailsList

                           where order.APIName.Equals(apiVal)

                             select order).ToList() ;

//var new1lst= newList.GroupBy(y=>y.APIVersion,).SelectMany()

            var productCounts = (from record in newList 

                 group record by new { record.APIVersion, record.appName } into grouping

                 orderby grouping.Key.APIVersion

                 select new  

                 { 

                     appName = grouping.Key.appName, 

                     Quantity = grouping.Count()

                 }).ToList();

            }

            return retVal;

        }

​

        public static void Main(string[] args)

        {

            try

            {

                List<String> retVal = processData(

                                      File.ReadAllLines("input.txt"));

                File.WriteAllLines("output.txt", retVal);

            }

            catch (IOException ex)

            {

                Console.WriteLine(ex.Message);

            }

        }

​

    }

}

​