汽车加油问题。一辆汽车加满油后可行驶n公里。旅途中有若干个加油站。设计一个有效算法，指出应在哪些加油站停靠加油，使沿途加油次数最少。-Vehicle refueling. Fill up the car after driving an n km. There are a number of gas stations journey. Design an efficient algorithm that at which stations should stop to refuel along the way so that the least number of refueling.