下The following is a vector-based implementation of the queue (for the interface and implementation of vectors refer to Chapter 2):面是队列的一种基于向量的实现(向量的接口和实现可参考第2章)：
For this queue of size n, the worst-case complexity of enqueue() and dequeue() is:对于规模为n的该队列，enqueue()和dequeue()的最坏时间复杂度分别为：
AO(n),O(n)
BO(1),O(1)
CO(n),O(1)
DO(n),O(log2(n))