Due to their exceptional mobility, simplified deployment process, and excellent line-of-sight communication links, Unmanned Aerial Vehicles (UAVs) are capable of delivering highly dependable and cost-effective communication services to ground users in emergency regions via their miniaturized base stations. When it comes to energy-efficient deployment and long-lasting service, this paper evaluates the possibility of placing rechargeable devices atop high-rise buildings in urban environments as potential sites for UAV deployment. For vast urban areas, characterized by an extensive number of buildings, this paper endeavors to minimize the energy consumption of the UAV swarm system by discretizing the transmission power of the UAVs. The optimal locations for deploying UAV base stations are determined by the Dijkstra Algorithm on the constructed directed weighted graphs (DWG-DA), ensuring uninterrupted network coverage in linear areas like urban streets or roads. The superiority of the DWG-DA algorithm is demonstrated through simulation experiments and algorithm comparison tests, taking into account various distribution patterns of UAVs and buildings.