力扣：622. 设计循环队列

￡神魔★判官ぃ 2024-03-26 21:12 25阅读 0赞

**题目描述：**  
[力扣：622. 设计循环队列][622.]  
![在这里插入图片描述][ed231b4166064265ba2ce22dadd2efb3.png]  
**解题思路：**  
1.本题可以用数组和链表解决，但是数组更加方便，更加高效，所以选择数组进行实现本题；  
2.添加`rear`和`front` 用来判断何时为空，什么时候为满，显然当`rear=front`为空，`rear+1=front`为满  
3.注意边界问题，这里采用`%（K+1）`来控制边界问题

typedef struct {
        
        int* a;
        int front;
        int rear;
        int k;
    } MyCircularQueue;
    
    //创建+初始化
    MyCircularQueue* myCircularQueueCreate(int k) 
    {
        
        MyCircularQueue* obj=(MyCircularQueue*)malloc(sizeof(MyCircularQueue));
    
        obj->a=(int*)malloc(sizeof(int)*(k+1));
        obj->front=obj->rear=0;
        obj->k=k;
    
        return obj;
    }
    
    //跟上边思路一样，判断是否为空
    bool myCircularQueueIsEmpty(MyCircularQueue* obj) 
    {
        
        return obj->front==obj->rear;
    }
    
    //跟上边思路一样，判断是否为满
    bool myCircularQueueIsFull(MyCircularQueue* obj) 
    {
        
        return (obj->rear+1)%(obj->k+1)==obj->front;
    }
    
    //添加一个新元素
    bool myCircularQueueEnQueue(MyCircularQueue* obj, int value) 
    {
        
    	//如果满了，所以就要return false
        if(myCircularQueueIsFull(obj))
        {
        
            return false;
        }
        //控制边界+添加新元素
        obj->a[obj->rear++]=value;
        obj->rear%=(obj->k+1);
        return true;
    }
    
    bool myCircularQueueDeQueue(MyCircularQueue* obj) 
    {
        
        if(myCircularQueueIsEmpty(obj)) return false;
        ++obj->front;
        obj->front%=(obj->k+1);
        return true;
    }
    
    int myCircularQueueFront(MyCircularQueue* obj)
    {
        
        if(myCircularQueueIsEmpty(obj)) return -1;
        else return obj->a[obj->front];
    }
    
    int myCircularQueueRear(MyCircularQueue* obj) 
    {
        
        if(myCircularQueueIsEmpty(obj)) return -1;
        else return obj->a[(obj->rear-1+obj->k+1)%(obj->k+1)];
    }
    
    void myCircularQueueFree(MyCircularQueue* obj) 
    {
        
        free(obj->a);
        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);
    */

![在这里插入图片描述][0ec668a1e0c0459eafb61aea18c165ac.png]

[622.]: https://leetcode.cn/problems/design-circular-queue/
[ed231b4166064265ba2ce22dadd2efb3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/3dc8b23d79e746f4a77e3feadbe1f169.png
[0ec668a1e0c0459eafb61aea18c165ac.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/7672173680e44300bb3f05840e516baf.png