设计实现双端队列。 你的实现需要支持以下操作：
MyCircularDeque(k)：构造函数,双端队列的大小为k。insertFront()：将一个元素添加到双端队列头部。 如果操作成功返回 true。insertLast()：将一个元素添加到双端队列尾部。如果操作成功返回 true。deleteFront()：从双端队列头部删除一个元素。 如果操作成功返回 true。deleteLast()：从双端队列尾部删除一个元素。如果操作成功返回 true。getFront()：从双端队列头部获得一个元素。如果双端队列为空，返回 -1。getRear()：获得双端队列的最后一个元素。 如果双端队列为空，返回 -1。isEmpty()：检查双端队列是否为空。isFull()：检查双端队列是否满了。提示：
所有值的范围为 [1, 1000]操作次数的范围为 [1, 1000]请不要使用内置的双端队列库。 class MyCircularDeque { private int[] queue = null; private int head, tail; private int size = 0; /** Initialize your data structure here. Set the size of the deque to be k. */ public MyCircularDeque(int k) { queue = new int[k]; head = 0; tail = queue.length - 1; } /** Adds an item at the front of Deque. Return true if the operation is successful. */ public boolean insertFront(int value) { if (isFull()) return false; size++; //插到队首，head往前移，因为减操作可能出现负数，所以需要加上queue的长度 head = (head + queue.length - 1) % queue.length; queue[head] = value; return true; } /** Adds an item at the rear of Deque. Return true if the operation is successful. */ public boolean insertLast(int value) { if (isFull()) return false; size++; //插到队尾，tail往后移 tail = (tail + 1) % queue.length; queue[tail] = value; return true; } /** Deletes an item from the front of Deque. Return true if the operation is successful. */ public boolean deleteFront() { if (isEmpty()) return false; size--; //删除队首，head往后移 head = (head + 1) % queue.length; return true; } /** Deletes an item from the rear of Deque. Return true if the operation is successful. */ public boolean deleteLast() { if (isEmpty()) return false; size--; //删除队尾，tail往前移，需要加上queue的长度，防止出现负数 tail = (tail + queue.length - 1) % queue.length; return true; } /** Get the front item from the deque. */ public int getFront() { if (isEmpty()) return -1; return queue[head]; } /** Get the last item from the deque. */ public int getRear() { if (isEmpty()) return -1; return queue[tail]; } /** Checks whether the circular deque is empty or not. */ public boolean isEmpty() { return size == 0; } /** Checks whether the circular deque is full or not. */ public boolean isFull() { return size == queue.length; } } /** * Your MyCircularDeque object will be instantiated and called as such: * MyCircularDeque obj = new MyCircularDeque(k); * boolean param_1 = obj.insertFront(value); * boolean param_2 = obj.insertLast(value); * boolean param_3 = obj.deleteFront(); * boolean param_4 = obj.deleteLast(); * int param_5 = obj.getFront(); * int param_6 = obj.getRear(); * boolean param_7 = obj.isEmpty(); * boolean param_8 = obj.isFull(); */