LC 0622 [M] Design Circular Queue - ALawliet/algorithms GitHub Wiki

we just need headIndex and the rest can be derived:
enqueue: (headIndex + n) % k
dequeue: (headIndex + 1) % k
tailIndex = (headIndex + n - 1) % k

class MyCircularQueue:

    def __init__(self, k: int):
        self.q = [0] * k
        self.headIndex = 0
        self.n = 0
        self.k = self.capacity = k
        

    def enQueue(self, value: int) -> bool:
        if self.n == self.k:
            return False
        nextHeadIndex = (self.headIndex + self.n) % self.k
        self.q[nextHeadIndex] = value # set the value at next available spot
        self.n += 1
        return True
        

    def deQueue(self) -> bool:
        if not self.n:
            return False
        nextHeadIndex = (self.headIndex + 1) % self.k
        self.headIndex = nextHeadIndex # just move the head forward
        self.n -= 1
        return True
        

    def Front(self) -> int: # where is the current head?
        if not self.n:
            return -1
        return self.q[self.headIndex]
        

    def Rear(self) -> int: # where is the current tail?
        if not self.n:
            return -1
        tailIndex = (self.headIndex + self.n - 1) % self.k
        return self.q[tailIndex]
        

    def isEmpty(self) -> bool:
        return not self.n
        

    def isFull(self) -> bool:
        return self.n == self.k
        


# 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()