习题3.13双端队列

bool Push(ElementType X, Deque D) //将元素X插入到双端队列D的头&＃xff1b;
{if ((D->Rear &＃43; 1) % D->MaxSize &＃61;&＃61; D->Front)return false;if (D->Front &＃61;&＃61; D->Rear){D->Data[D->Front] &＃61; X;D->Rear &＃61; (D->Rear &＃43; 1) % D->MaxSize;return true;}D->Front &＃61; (D->Front - 1&＃43; D->MaxSize) % D->MaxSize;D->Data[D->Front] &＃61; X;return true;
}ElementType Pop(Deque D) //删除双端队列D的头元素&＃xff0c;并返回&＃xff1b;
{ElementType x;if (D->Front &＃61;&＃61; D->Rear)return ERROR;x &＃61; D->Data[D->Front];D->Front &＃61; (D->Front &＃43;1) % D->MaxSize;return x;
}bool Inject(ElementType X, Deque D) //将元素X插入到双端队列D的尾部&＃xff1b;
{if ((D->Rear &＃43; 1) % D->MaxSize &＃61;&＃61; D->Front)return false;D->Data[D->Rear] &＃61; X;D->Rear &＃61; (D->Rear &＃43; 1) % D->MaxSize;return true;
}ElementType Eject(Deque D) //删除双端队列D的尾部元素&＃xff0c;并返回。
{ElementType x;if (D->Front &＃61;&＃61; D->Rear)return ERROR;D->Rear &＃61; (D->Rear - 1&＃43; D->MaxSize) % D->MaxSize;x &＃61; D->Data[D->Rear];return x;
}

细心的你会发现&＃xff0c;代码中有一段其实可以去掉&＃xff0c;效果是一样的&＃xff0c;读者自行思考。

if (D->Front &＃61;&＃61; D->Rear){D->Data[D->Front] &＃61; X;D->Rear &＃61; (D->Rear &＃43; 1) % D->MaxSize;return true;}