# Design Circular Queue

## Solution

``````
#!/usr/bin/env python
# coding=utf-8
#
# Author: Lucas
# Date: 2019-08-31 21:01:03

class MyCircularQueue:

def __init__(self, k: int):
"""
Initialize your data structure here. Set the size of the queue to be k.
"""
self.data = [None] * 2 * k
self.start = 0
self.end = 0
self.size = k

def enQueue(self, value: int) -> bool:
"""
Insert an element into the circular queue. Return true if the operation is successful.
"""
if self.end - self.start >= self.size:
return False
if self.end == self.size:
for i in range(self.end - self.start):
self.data[i] = self.data[self.start + i]
self.data[self.start + i] = None
self.start, self.end = 0, (self.end - self.start)
self.data[self.end] = value
self.end += 1
return True

def deQueue(self) -> bool:
"""
Delete an element from the circular queue. Return true if the operation is successful.
"""
if self.end == self.start:
return False
ans = self.data[self.start]
self.data[self.start] = None
self.start += 1
return True

def Front(self) -> int:
"""
Get the front item from the queue.
"""
if self.isEmpty():
return -1
return self.data[self.start]

def Rear(self) -> int:
"""
Get the last item from the queue.
"""
if self.isEmpty():
return -1
return self.data[self.end - 1]

def isEmpty(self) -> bool:
"""
Checks whether the circular queue is empty or not.
"""
return self.end == self.start

def isFull(self) -> bool:
"""
Checks whether the circular queue is full or not.
"""
return self.end - self.start == self.size

# 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()

``````