In other words, some elevators can only stop at odd floors, and some elevators can only stop at even floors. Or some can only stop at 1 floor and above N floor, and some can stop below N floor.

The number of elevators in a commercial office building is determined by the building area. A 200,000-square-meter 30-story large office building generally needs about 8 elevators. It takes a lot of time for all eight elevators to run up and down on the 30th floor, so the slope is very poor. If we continue to add elevators, it will only increase the cost. Therefore, we should limit the elevator control mode. For example, four of the eight elevators only stay on odd floors, and the rest are on even floors, which can speed up efficiency.