Askar bot

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSTest
{
    internal class Program
    {
        static void Main(string[] args)
        {
            TestCase();
            Console.ReadKey();
        }

        private static readonly char[] alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

        private static string[] AvailableParkingSpaces(int columns, int rows, string[] busyParkingSpaces, TimeSpan[] startTimes,
            TimeSpan[] endTimes, TimeSpan newParkingTime, int newParkingDuration)
        {
            IDictionary<string, List<TimeSpan>> parkingPlaces = new Dictionary<string, List<TimeSpan>>();
            for (int i = 0; i < columns; i++)
            {
                for (int j = 0; j < rows; j++)
                {
                    parkingPlaces.Add(alpha[i].ToString() + (j + 1).ToString(), null);
                }
            }

            for (int i = 0; i < busyParkingSpaces.Length; i++)
            {
                if (parkingPlaces[busyParkingSpaces[i]] == null)
                {
                    parkingPlaces[busyParkingSpaces[i]] = new List<TimeSpan>();
                }
                parkingPlaces[busyParkingSpaces[i]].Add(startTimes[i]);
                parkingPlaces[busyParkingSpaces[i]].Add(endTimes[i]);
            }

            List<string> availablePlaces = new List<string>();

            foreach (var place in parkingPlaces)
            {
                if (place.Value != null)
                {
                    if (IsAllOk(place, newParkingTime, newParkingDuration))
                    {
                        availablePlaces.Add(place.Key);
                    }
                }
                else
                {
                    availablePlaces.Add(place.Key);
                }
            }

            return availablePlaces.ToArray();
        }

        private static bool IsAllOk(KeyValuePair<string, List<TimeSpan>> place, TimeSpan parkingTime, int duration)
        {
            for (int j = 0; j < place.Value.Count; j += 2)
            {
                if (place.Value[j] <= parkingTime && place.Value[j + 1] > parkingTime)
                {
                    return false;
                }

                if (place.Value[j] > parkingTime)
                {
                    if (place.Value[j] < parkingTime + TimeSpan.FromMinutes(duration))
                    {
                        return false;
                    }
                }
            }
            return true;
        }

        public static void TestCase()
        {
            string[] busyIntervals = new string[] { "B1", "C3", "A2", "B3", "C3", "A1", "B1", "C2", "A3" };
            TimeSpan[] startTimes = new TimeSpan[] { TimeSpan.FromHours(10), TimeSpan.FromHours(15.5), TimeSpan.FromHours(6),
                TimeSpan.FromHours(9), TimeSpan.FromHours(8), TimeSpan.FromHours(4), TimeSpan.FromHours(14), TimeSpan.FromHours(10),
                TimeSpan.FromHours(5) };
            TimeSpan[] endTimes = new TimeSpan[] { TimeSpan.FromHours(14), TimeSpan.FromHours(20), TimeSpan.FromHours(12.3),
                TimeSpan.FromHours(10), TimeSpan.FromHours(11.5), TimeSpan.FromHours(16.75), TimeSpan.FromHours(18), TimeSpan.FromHours(22),
                TimeSpan.FromHours(17) };

            string[] outArray = AvailableParkingSpaces(3, 3, busyIntervals, startTimes, endTimes, TimeSpan.FromHours(11), 330);

            Console.WriteLine(string.Join(", ", outArray));
        }
    }
}