using System; 

using System.Globalization;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        string[,] array = new string[6, 2];

        array[0, 0] = "5847";

        array[0, 1] = "started";

        array[1, 0] = "5846";

        array[1, 1] = "ended";

        array[2, 0] = "5846";

        array[2, 1] = "started";

        array[3, 0] = "5845";

        array[3, 1] = "ended";

        array[4, 0] = "5845";

        array[4, 1] = "started";

        array[5, 0] = "5844";

        array[5, 1] = "ended";

        var result = Enumerable

                    .Range(0, array.GetLength(0))

                    .Select(row => new Foo { id = int.Parse(array[row, 0]), ended = (array[row, 1] == "ended") })

                    .GroupBy(g=> g.id)

                    .Select( g=> new Foo{ id=g.Key, ended= g.Max(r=> r.ended)})

                    .Where(x=> !x.ended);

        result.Dump();

    }

}   

​

public class Foo

{

    public int id { get; set; }

    public bool ended { get; set; }

}

​

​