A.1和5 B.2和4 C.4和2 D.5和1
A.1243 B.2134 C.1432 D.4312 E.3214
A.Q->rear==Q->front B.Q->rear==Q->front+1 C.Q->front==(Q->rear+1)%n D.Q->front==(Q->rear-1)%n