c语言刷 队列题记录

622. 设计循环队列

https://blog.csdn.net/Galaxy_n/article/details/115978544

typedef struct {
    int *arrs;
    int front;
    int rear;
    int size;
} MyCircularQueue;

/* 判断队列是否为空 */
bool myCircularQueueIsEmpty(MyCircularQueue* obj)
{
    return obj->front == obj->rear;
}

/* 判断队列是否满了 */
bool myCircularQueueIsFull(MyCircularQueue* obj)
{
    int rearNext = obj->rear + 1;
    if (rearNext == obj->size + 1) {
        rearNext = 0;
    }
    return rearNext == obj->front;
}

MyCircularQueue* myCircularQueueCreate(int k)
{
    MyCircularQueue *obj = malloc(sizeof(MyCircularQueue));
    obj->arrs = (int *)malloc(sizeof(int) * (k + 1));
    obj->front = 0;
    obj->rear = 0;
    obj->size = k;
    return obj;
}

/* 插入元素入队（尾插） */
bool myCircularQueueEnQueue(MyCircularQueue* obj, int value)
{
    if (myCircularQueueIsFull(obj)) {
        return false;
    }
    obj->arrs[obj->rear++] = value;
    if (obj->rear == obj->size + 1) {
        obj->rear = 0;
    }
    return true;
}

/* 从队列中删除元素 */
bool myCircularQueueDeQueue(MyCircularQueue* obj)
{
    if (myCircularQueueIsEmpty(obj)) {
        return false;
    }
    obj->front++; // 要考虑“循环”
    if (obj->front == obj->size + 1) {
        obj->front = 0;
    }
    return true;
}

/* 取队列首元素 */
int myCircularQueueFront(MyCircularQueue* obj)
{
    if (myCircularQueueIsEmpty(obj)) {
        return -1;
    }

    return obj->arrs[obj->front];
}

/* 取队列尾元素 */
int myCircularQueueRear(MyCircularQueue* obj)
{
    if (myCircularQueueIsEmpty(obj)) {
        return -1;
    }

    int rearPre = obj->rear - 1;
    if (rearPre == -1) {
        rearPre = obj->size;
    }
    return obj->arrs[rearPre];
}

void myCircularQueueFree(MyCircularQueue* obj)
{
    free(obj->arrs);
    free(obj);
}

/**
 * Your MyCircularQueue struct will be instantiated and called as such:
 * MyCircularQueue* obj = myCircularQueueCreate(k);
 * bool param_1 = myCircularQueueEnQueue(obj, value);

 * bool param_2 = myCircularQueueDeQueue(obj);

 * int param_3 = myCircularQueueFront(obj);

 * int param_4 = myCircularQueueRear(obj);

 * bool param_5 = myCircularQueueIsEmpty(obj);

 * bool param_6 = myCircularQueueIsFull(obj);

 * myCircularQueueFree(obj);
*/

641. 设计循环双端队列