该算法模拟渡口管理。过江渡船每次能载10辆车过江，过江车辆分为客车类和货车类，上渡船有如下规定：同类车先到先上船，客车先于货车上渡船，且每上4辆客车，才允许上一辆货车。若等待客车不足4辆，则从货车代替，若无货车等待允许客车上船。-the algorithm simulation ferry management. Jiang Ferry each can carry 10 cars crossing the river, crossing the river into passenger vehicles and goods category, Ferry on the following provisions : Similar cars first come-first embarkation, the first passenger ferry in the truck and four on each passenger will be permitted on a lorry. If waiting for the bus less than four, then replace the truck, without waiting for the lorry to allow passenger embarkation.