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/**

* Design your implementation of the circular queue. The circular queue is a

* linear data structure in which the operations are performed based on FIFO

* (First In First Out) principle and the last position is connected back to

* the first position to make a circle. It is also called "Ring Buffer".

*

* One of the benefits of the circular queue is that we can make use of the

* spaces in front of the queue. In a normal queue, once the queue becomes

* full, we cannot insert the next element even if there is a space in front

* of the queue. But using the circular queue, we can use the space to store

* new values.

*

* Your implementation should support following operations:

*

* MyCircularQueue(k): Constructor, set the size of the queue to be k.

* Front: Get the front item from the queue. If the queue is empty, return -1.

* Rear: Get the last item from the queue. If the queue is empty, return -1.

* enQueue(value): Insert an element into the circular queue. Return true if the operation is successful.

* deQueue(): Delete an element from the circular queue. Return true if the operation is successful.

* isEmpty(): Checks whether the circular queue is empty or not.

* isFull(): Checks whether the circular queue is full or not.

*

* Example:

*

* MyCircularQueue circularQueue = new MycircularQueue(3); // set the size to be 3

* circularQueue.enQueue(1); // return true

* circularQueue.enQueue(2); // return true

* circularQueue.enQueue(3); // return true

* circularQueue.enQueue(4); // return false, the queue is full

* circularQueue.Rear(); // return 3

* circularQueue.isFull(); // return true

* circularQueue.deQueue(); // return true

* circularQueue.enQueue(4); // return true

* circularQueue.Rear(); // return 4

*

* Note:

* All values will be in the range of [0, 1000].

* The number of operations will be in the range of [1, 1000].

* Please do not use the built-in Queue library.

*/

public class DesignCircularQueue622 {

class MyCircularQueue {

private Node head;

private int capacity;

private int size;

/** Initialize your data structure here. Set the size of the queue to be k. */

public MyCircularQueue(int k) {

this.head = new Node();

this.head.prev = head;

this.head.next = head;

this.capacity = k;

this.size = 0;

}

/** Insert an element into the circular queue. Return true if the operation is successful. */

public boolean enQueue(int value) {

if (isFull()) return false;

Node newNode = new Node(value);

newNode.next = this.head;

newNode.prev = this.head.prev;

this.head.prev.next = newNode;

this.head.prev = newNode;

this.size++;

return true;

}

/** Delete an element from the circular queue. Return true if the operation is successful. */

public boolean deQueue() {

if (isEmpty()) return false;

dislink(this.head.next);

this.size--;

return true;

}

private void dislink(Node node) {

node.next.prev = node.prev;

node.prev.next = node.next;

}

/** Get the front item from the queue. */

public int Front() {

if (isEmpty()) return -1;

return this.head.next.value;

}

/** Get the last item from the queue. */

public int Rear() {

if (isEmpty()) return -1;

return this.head.prev.value;

}

/** Checks whether the circular queue is empty or not. */

public boolean isEmpty() {

return this.size == 0;

}

/** Checks whether the circular queue is full or not. */

public boolean isFull() {

return this.size == this.capacity;

}

class Node {

Node prev;

Node next;

int value;

Node() {

this.value = -1;

}

Node(int value) {

this.value = value;

}

}

}

class MyCircularQueue2 {

private int[] cache;

private int head;

private int capacity;

private int size;

/** Initialize your data structure here. Set the size of the queue to be k. */

public MyCircularQueue(int k) {

this.cache = new int[k + 1];

this.head = 0;

this.capacity = k;

this.size = 0;

}

/** Insert an element into the circular queue. Return true if the operation is successful. */

public boolean enQueue(int value) {

if (isFull()) return false;

this.size++;

this.cache[(this.head + this.size) % this.cache.length] = value;

return true;

}

/** Delete an element from the circular queue. Return true if the operation is successful. */

public boolean deQueue() {

if (isEmpty()) return false;

this.head++;

this.head = this.head % this.cache.length;

this.size--;

return true;

}

/** Get the front item from the queue. */

public int Front() {

if (isEmpty()) return -1;

return this.cache[(this.head + 1) % this.cache.length];

}

/** Get the last item from the queue. */

public int Rear() {

if (isEmpty()) return -1;

return this.cache[(this.head + this.size) % this.cache.length];

}

/** Checks whether the circular queue is empty or not. */

public boolean isEmpty() {

return this.size == 0;

}

/** Checks whether the circular queue is full or not. */

public boolean isFull() {

return this.size == this.capacity;

}

}

/**

* Your MyCircularQueue object will be instantiated and called as such:

* MyCircularQueue obj = new MyCircularQueue(k);

* boolean param_1 = obj.enQueue(value);

* boolean param_2 = obj.deQueue();

* int param_3 = obj.Front();

* int param_4 = obj.Rear();

* boolean param_5 = obj.isEmpty();

* boolean param_6 = obj.isFull();

*/

}