leetcode：622. 设计循环队列【循环队列板子】

设计思路

用一个数组模拟，要多留一个空位
front和rear记录头尾，注意rear是最后一个元素的后一个，初始都是0
空的话两个相等，满的话rear + 1 = front（mod k + 1)
然后最后一个元素注意是rear - 1（mod k + 1）取出来的
其他的话就双指针移动即可

Ac code

class MyCircularQueue:

    # 循环队列学习

    def __init__(self, k: int):
        # 为了区分满和空，存储空间会多一个位置
        self.front = self.rear = 0
        self.elements = [0] * (k + 1)

    def enQueue(self, value: int) -> bool:
        if self.isFull():
            return False
        self.elements[self.rear] = value
        self.rear = (self.rear + 1) % len(self.elements)
        return True


    def deQueue(self) -> bool:
        if self.isEmpty():
            return False
        self.front = (self.front + 1) % len(self.elements)
        return True


    def Front(self) -> int:
        return -1 if self.isEmpty() else self.elements[self.front]


    def Rear(self) -> int:
        return -1 if self.isEmpty() else self.elements[(self.rear - 1) % len(self.elements)]


    def isEmpty(self) -> bool:
        return self.front == self.rear


    def isFull(self) -> bool:
        return (self.rear + 1) % len(self.elements) == self.front



# 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()

总结

循环队列学习