circular_queue.py

class CircularQueue:
    def __init__(self, k):
        self.queue = [None] * k
        self.head = self.tail = -1
        self.size = 0

    def enqueue(self, item):
        if self.is_full():
            return False
        if self.is_empty():
            self.head = 0
        self.tail = (self.tail + 1) % len(self.queue)
        self.queue[self.tail] = item
        self.size += 1
        return True

    def dequeue(self):
        if self.is_empty():
            return None
        item = self.queue[self.head]
        if self.head == self.tail:
            self.head = self.tail = -1
        else:
            self.head = (self.head + 1) % len(self.queue)
        self.size -= 1
        return item

    def is_empty(self):
        return self.size == 0

    def is_full(self):
        return self.size == len(self.queue)

    def get_size(self):
        return self.size