el

 public enum Moving {
        None,
        Down=1,
        Up=2
    }
    public struct State {
        public int Elevator;
        public int Floor { get; set; }
        public Moving Moving { get; set; }
    }
    class Building {

        public int ElevatorsCount { get; set; } = 20;
        public int FloorsCount { get; set; } = 100;
        public int TimeForOneFloor { get; set; } = 2; // 2 sec
        public int OpenDoorsTime { get; set; } = 5; // 5 sec
        public List<State> States = new List<State>(20);
    }
    class Program
    {
        public static int func(Building building, Moving moving, int fromFloor)
        {
            int elevator = -1;

            var x = int.MaxValue;
            for (int i = 0; i < building.States.Count; i++)
            {
                if (moving == Moving.Up && building.States[i].Moving == Moving.Up)
                {
                    var f = (fromFloor - building.States[i].Floor) * building.TimeForOneFloor;
                    if (f < x)
                    {
                        x = f;
                        elevator = building.States[i].Elevator;
                    }
                }
                if (moving == Moving.Down && building.States[i].Moving == Moving.Down)
                {
                    var f = (fromFloor - building.States[i].Floor) * building.TimeForOneFloor;
                    if (f < x)
                    {
                        x = f;
                        elevator = building.States[i].Elevator;
                    }
                }
                else if (building.States[i].Moving == Moving.None)
                {
                    var f = (fromFloor - building.States[i].Floor) * building.TimeForOneFloor + building.OpenDoorsTime;
                    if (f < x)
                    {
                        x = f;
                        elevator = building.States[i].Elevator;
                    }
                }

            }

            return elevator;
        }