# 622. Design Circular Queue

#### Medium

***

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.

Implementation the `MyCircularQueue` class:

* `MyCircularQueue(k)` Initializes the object with the size of the queue to be `k`.
* `int Front()` Gets the front item from the queue. If the queue is empty, return `-1`.
* `int Rear()` Gets the last item from the queue. If the queue is empty, return `-1`.
* `boolean enQueue(int value)` Inserts an element into the circular queue. Return `true` if the operation is successful.
* `boolean deQueue()` Deletes an element from the circular queue. Return `true` if the operation is successful.
* `boolean isEmpty()` Checks whether the circular queue is empty or not.
* `boolean isFull()` Checks whether the circular queue is full or not.

You must solve the problem without using the built-in queue data structure in your programming language. 

 

**Example 1:**

<pre><code>Input
["MyCircularQueue", "enQueue", "enQueue", "enQueue", "enQueue", "Rear", "isFull", "deQueue", "enQueue", "Rear"]
[[3], [1], [2], [3], [4], [], [], [], [4], []]
<strong>Output
</strong>[null, true, true, true, false, 3, true, true, true, 4]
<strong>Explanation
</strong>MyCircularQueue myCircularQueue = new MyCircularQueue(3);
myCircularQueue.enQueue(1); // return True
myCircularQueue.enQueue(2); // return True
myCircularQueue.enQueue(3); // return True
myCircularQueue.enQueue(4); // return False
myCircularQueue.Rear();     // return 3
myCircularQueue.isFull();   // return True
myCircularQueue.deQueue();  // return True
myCircularQueue.enQueue(4); // return True
myCircularQueue.Rear();     // return 4
</code></pre>

&#x20;

**Constraints:**

* `1 <= k <= 1000`
* `0 <= value <= 1000`
* At most `3000` calls will be made to `enQueue`, `deQueue`, `Front`, `Rear`, `isEmpty`, and `isFull`.

```python
class MyCircularQueue:

    def __init__(self, k: int):
        self.q = []
        self.elements = 0
        self.k = k

    def enQueue(self, value: int) -> bool:
        if self.elements == self.k:
            return False
        self.q.append(value)
        self.elements += 1
        return True

    def deQueue(self) -> bool:
        if self.elements == 0:
            return False
        self.q.pop(0)
        self.elements -= 1
        return True

    def Front(self) -> int:
        if self.elements == 0:
            return -1
        return self.q[0]

    def Rear(self) -> int:
        if self.elements == 0:
            return -1
        return self.q[-1]

    def isEmpty(self) -> bool:
        return len(self.q) == 0
        

    def isFull(self) -> bool:
        return self.elements == self.k


# Your MyCircularQueue object will be instantiated and called as such:
# obj = MyCircularQueue(k)
# param_1 = obj.enQueue(value)
# param_2 = obj.deQueue()
# param_3 = obj.Front()
# param_4 = obj.Rear()
# param_5 = obj.isEmpty()
# param_6 = obj.isFull()
```