【java】622. Design Circular Queue

原文链接https://leetcode-cn.com/problems/design-circular-queue/description/

这个就是基础的循环队列的相关问题。问题难点主要是判断空和满的情况。

class MyCircularQueue {

        int[] queue;
		int front;
		int rear;
		int size;

	    /** Initialize your data structure here. Set the size of the queue to be k. */
	    public MyCircularQueue(int k) {
	        queue = new int[k+1];
	        size = k;
	    }
	    
	    /** Insert an element into the circular queue. Return true if the operation is successful. */
	    public boolean enQueue(int value) {
	        if(isFull()) return false;
	        queue[rear] = value;
            rear = (rear+1)%(size+1);
	        return true;
	    }
	    
	    /** Delete an element from the circular queue. Return true if the operation is successful. */
	    public boolean deQueue() {
	        if(isEmpty()) return false;
	        front = (front+1)%(size+1);
	        return true;
	    }
	    
	    /** Get the front item from the queue. */
	    public int Front() {
	    	if(isEmpty()) return -1;
	        return queue[front];
	    }
	    
	    /** Get the last item from the queue. */
	    public int Rear() {
	        if(isEmpty()) return -1;
	        return queue[(rear+size)%(size+1)];
	    }
	    
	    /** Checks whether the circular queue is empty or not. */
	    public boolean isEmpty() {
	        return front == rear;
	    }
	    
	    /** Checks whether the circular queue is full or not. */
	    public boolean isFull() {
	        return (rear+1)%(size+1) == front;
	    }
}