Leetcode 循环队列

class MyCircularQueue:

    def __init__(self, k: int):
        """
        Initialize your data structure here. Set the size of the queue to be k.
        """
        self.queue = [0]*(k+1)      #牺牲一个存储空间
        self.head = 0
        self.tail = 0

    def enQueue(self, value: int) -> bool:
        """
        Insert an element into the circular queue. Return true if the operation is successful.
        """
        if self.isFull():
            return False
        else:
            self.queue[self.tail] = value
            self.tail = (self.tail+1)%len(self.queue)
            return True
        

    def deQueue(self) -> bool:
        """
        Delete an element from the circular queue. Return true if the operation is successful.
        """
        if self.tail == self.head:
            return False
        else:
            self.head = (self.head+1)%len(self.queue)
            return True
        

    def Front(self) -> int:
        """
        Get the front item from the queue.
        """
        if not self.isEmpty():
            return self.queue[self.head]
        else:
            return -1       #因为只存储正数，且返回值为 int 我只能写 -1 了,如果有需要可以根据需要修改这里的返回值
        

    def Rear(self) -> int:
        """
        Get the last item from the queue.
        """
        if not self.isEmpty():
            return self.queue[(self.tail-1+len(self.queue))%len(self.queue)]
        else:
            return -1       #因为只存储正数，且返回值为 int 我只能写 -1 了,如果有需要可以根据需要修改这里的返回值
        

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

    def isFull(self) -> bool:
        """
        Checks whether the circular queue is full or not.
        """
        return (self.tail+1)%len(self.queue) == self.head