class CircularQueue:
def __init__(self, size):
self.size = size
self.head = 0
self.tail = 0
self.buffer = [None] * size
self.length = 0
def enqueue(self, value):
self.length += 1
self.buffer[self.tail] = value
self.tail += 1
if self.tail >= self.size:
self.tail = 0
def dequeue(self):
self.length -= 1
value = self.buffer[self.head]
self.head += 1
if self.head >= self.size:
self.head = 0
return value
