设计循环队列
1、定義數據結構??tail head 頭尾指針，隊列buf queue ，隊列長度 size? ?，已存數據長度 len?
typedef?struct?myQueue{
????int*?queue;
????int?head;
????int?tail;
????int?size;
????int?len;
}?MyCircularQueue;
2.初始化 數據結構
/**?Initialize?your?data?structure?here.?Set?the?size?of?the?queue?to?be?k.?*/
?
MyCircularQueue*?myCircularQueueCreate(int?k)?{
????MyCircularQueue*?obj=malloc(sizeof(MyCircularQueue));
????obj->queue=malloc(k*sizeof(int));
????obj->head=0;
????obj->tail=0;
????obj->size=k;
????obj->len?=?0;
????return?obj;
}
3.如果已存在數據長度為0 則為空
/**?Checks?whether?the?circular?queue?is?empty?or?not.?*/
bool?myCircularQueueIsEmpty(MyCircularQueue*?obj)?{
????return?(obj->len==0);//&&((obj->queue)[obj->head]==-1);
}
4、如果已存在數據長度等于queue的長度則隊列為滿
/**?Checks?whether?the?circular?queue?is?full?or?not.?*/
bool?myCircularQueueIsFull(MyCircularQueue*?obj)?{
????return?(obj->len==obj->size);
}
5、向尾指針插入數據，尾指針總是指向當前有效數據的下個地址，已存在數據長度加1
/**?Insert?an?element?into?the?circular?queue.?Return?true?if?the?operation?is?successful.?*/
bool?myCircularQueueEnQueue(MyCircularQueue*?obj,?int?value)?{
????if(myCircularQueueIsFull(obj))?return?false;
????(obj->queue)[obj->tail]=value;
????obj->tail?=?(obj->tail?+?1?)%?obj->size;??
????obj->len?++;
????return?true;
}
6、從頭指針開始刪除隊列中元素，已存在數據長度減1，頭指針加一
/**?Delete?an?element?from?the?circular?queue.?Return?true?if?the?operation?is?successful.?*/
bool?myCircularQueueDeQueue(MyCircularQueue*?obj)?{
????if(myCircularQueueIsEmpty(obj))?return?false;
???????obj->head?=?(obj->head?+?1)?%?obj->size;
???????obj->len?--;
????return?true;
}
7、獲取有效數據第一個元素
/**?Get?the?front?item?from?the?queue.?*/
int?myCircularQueueFront(MyCircularQueue*?obj)?{
?????if(myCircularQueueIsEmpty(obj))?return?-1;
????return?(obj->queue)[obj->head];
}
8、獲取有效數據最后一個元素
/**?Get?the?last?item?from?the?queue.?*/
int?myCircularQueueRear(MyCircularQueue*?obj)?{
????if(myCircularQueueIsEmpty(obj))?return?-1;?
????if(obj->tail?==?0)
????return?(obj->queue)[obj->size?-?1];
????else
?????return?(obj->queue)[obj->tail?-?1];
}
9、釋放queue
void?myCircularQueueFree(MyCircularQueue*?obj)?{
????if(obj&&obj->queue)
????{
???????free(obj->queue);
???????free(obj);
????}??
}
總結
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