数据结构之循环队列

数据结构之循环队列

#include <stdio.h>

#include <stdlib.h>

#define kMyCycleQueueDefaulMaxSize 10

typedef struct MyCycleQueueNode

{

    int data;

    struct MyCycleQueueNode *front;

}MyCycleQueueNode;

typedef struct MyCycleQueue

{

    int length;

    int maxSize;

    MyCycleQueueNode *head;

    MyCycleQueueNode *real;

}MyCycleQueue;

MyCycleQueue* MyCycleQueue_create(int maxSize)

{

    MyCycleQueue *queue = (MyCycleQueue *)malloc(sizeof(MyCycleQueue));

    queue->length = 0;

//    queue->maxSize = maxSize < 10 ? kMyCycleQueueDefaulMaxSize : maxSize;

    queue->maxSize = 3;

    queue->head = NULL;

    queue->real = NULL;

    

    return queue;

}

int MyCycleQueue_isEmpty(MyCycleQueue *queue)

{

    if(queue != NULL)

    {

        return queue->length == 0 ? 1 : 0;

    }

    return 1;

}

int MyCycleQueue_isFull(MyCycleQueue *queue)

{

    if(queue != NULL)

    {

        if(queue->length < queue->maxSize)

        {

            return 0;

        }

    }

    return 1;

}

void MyCycleQueue_enqueue(MyCycleQueue *queue, int data)

{

    if(queue == NULL) return; // null

    

    if(MyCycleQueue_isFull(queue)) return;

    

    MyCycleQueueNode *node = NULL;

    if(queue->real != NULL && queue->real->front != NULL)

    {

        node = queue->real->front;

    }

    else

    {

        node = (MyCycleQueueNode *)malloc(sizeof(MyCycleQueueNode));

        node->front = NULL;        

    }

    node->data = data;

    

    if(queue->head == NULL)

    {

        queue->head = node;

    }

    else

    {

        queue->real->front = node;

    }

    queue->real = node;

    queue->length ++;

    

    if(queue->maxSize <= queue->length && queue->real->front == NULL)

    {

        queue->real->front = queue->head;

    }

}

int MyCycleQueue_dequeue(MyCycleQueue *queue)

{

    if(queue == NULL || queue->length == 0) return 0;

    

    MyCycleQueueNode *node = queue->head;

    queue->head = node->front;

    queue->length --;

    int data = node->data;

    node->data = 0;

    return data;

}

void MyCycleQueue_myprintln(MyCycleQueue *queue)

{

    if(MyCycleQueue_isEmpty(queue)) return;

    

    printf("\n");

    

    MyCycleQueueNode *p = queue->head;

    

    for(int i = 0; i < queue->length; i ++)

    {

        printf("%d  ", p->data);

        p = p->front;

    }

}

void main()

{

    MyCycleQueue *queue = MyCycleQueue_create(3);

    MyCycleQueue_enqueue(queue, 10);

    MyCycleQueue_enqueue(queue, 9);

    MyCycleQueue_enqueue(queue, 30);

    

    MyCycleQueue_enqueue(queue, 100);

    

    MyCycleQueue_myprintln(queue);

    

    int data = MyCycleQueue_dequeue(queue);

    

    MyCycleQueue_myprintln(queue);

    

    MyCycleQueue_enqueue(queue, 99);

    

     MyCycleQueue_myprintln(queue);

}