using System;

using System.Collections.Generic;

using System.Linq;

​

​

public class Program

{

    private static int TotalCycles;

​

​

    public static void Main()

    {

        var LstCyclces = new List<Cycle>();

        Cycle cycle = null;

​

        cycle = new Cycle(); //cycle 1

        cycle.Cars = new List<Car>();

        cycle.Cars.Add(new Car { CarId = 1, Location = 40 });

        cycle.Cars.Add(new Car { CarId = 2, Location = 21 });

        cycle.Cars.Add(new Car { CarId = 3, Location = 5 });

        cycle.Cars.Add(new Car { CarId = 4, Location = 15 });

        LstCyclces.Add(cycle);

​

        cycle = new Cycle(); //cycle2

        cycle.Cars = new List<Car>();

        cycle.Cars.Add(new Car { CarId = 1, Location = 40 }); //same location

        cycle.Cars.Add(new Car { CarId = 2, Location = 57 }); //changed location

        cycle.Cars.Add(new Car { CarId = 3, Location = 100 }); //changed location

        cycle.Cars.Add(new Car { CarId = 4, Location = 7 }); //changed location

        cycle.Cars.Add(new Car { CarId = 7, Location = 2 }); //new attended ( vs previous cycle)

        LstCyclces.Add(cycle);

​

        cycle = new Cycle(); //cycle3

        cycle.Cars = new List<Car>();

        cycle.Cars.Add(new Car { CarId = 1, Location = 40 }); //same

        cycle.Cars.Add(new Car { CarId = 2, Location = 5 }); //changed Location

        cycle.Cars.Add(new Car { CarId = 4, Location = 1 }); //changed Location

        cycle.Cars.Add(new Car { CarId = 9, Location = 7 }); //new attended ( vs previous cycle)

        LstCyclces.Add(cycle);

​

​

        var cycleToCheck = 2;

​

        var query = LstCyclces.FirstOrDefault(c => c.CycleNum == cycleToCheck).Cars

                                    .Where(c => LstCyclces.FirstOrDefault(p => p.CycleNum == cycleToCheck - 1).Cars

                                                .Any(ca => ca.CarId == c.CarId && Math.Abs(c.Location - ca.Location) < 40));

        var result = query.SelectMany(t1 => query.Select(t2 => Tuple.Create(t1, t2)))

                .Where(x => Math.Abs(x.Item1.Location - x.Item2.Location) < 65 && x.Item1.CarId < x.Item2.CarId);

​

        foreach (var r in result)

        {           

            Console.WriteLine("{0} - {1}", r.Item1.CarId, r.Item2.CarId);

        }

    }

​

​

    private class Car

    {

        public int CarId;

        public int Location;

    }

​

​

    private class Cycle

    {

        public readonly int CycleNum;

        public List<Car> Cars;

​

​

        public Cycle()

        {

            this.CycleNum = (++TotalCycles);

        }

    }

}