Инициализируйте queue.front как -1 или 0 в Designing Circular Queue

Я изучаю Очередь из задачи Дизайн круговой очереди - LeetCode

Design your implementation of the circular queue. The circular queue is a linear data structure in which the operations are performed based on FIFO (First In First Out) principle and the last position is connected back to the first position to make a circle. It is also called "Ring Buffer".

One of the benefits of the circular queue is that we can make use of the spaces in front of the queue. In a normal queue, once the queue becomes full, we cannot insert the next element even if there is a space in front of the queue. But using the circular queue, we can use the space to store new values.

Your implementation should support following operations:

• MyCircularQueue(k): Constructor, set the size of the queue to be k.
• Front: Get the front item from the queue. If the queue is empty, return -1.
• Rear: Get the last item from the queue. If the queue is empty, return -1.
• enQueue(value): Insert an element into the circular queue. Return true if the operation is successful.
• deQueue(): Delete an element from the circular queue. Return true if the operation is successful.
• isEmpty(): Checks whether the circular queue is empty or not.
• isFull(): Checks whether the circular queue is full or not.

Example:

MyCircularQueue circularQueue = new MyCircularQueue(3); // set the size to be 3
circularQueue.enQueue(1);  // return true
circularQueue.enQueue(2);  // return true
circularQueue.enQueue(3);  // return true
circularQueue.enQueue(4);  // return false, the queue is full
circularQueue.Rear();  // return 3
circularQueue.isFull();  // return true
circularQueue.deQueue();  // return true
circularQueue.enQueue(4);  // return true
circularQueue.Rear();  // return 4

Note:

• All values will be in the range of [0, 1000].
• The number of operations will be in the range of [1, 1000].
• Please do not use the built-in Queue library.

Я подражаю учебнику Гудрича Структуры данных и алгоритмы в Python и написал понятное решение.

1, только три данных (_queue, _len и _front)

2, инициализировать self._front как 0

class MyCircularQueue:
     #Runtime: 76 ms, faster than 53.17%
     #Memory Usage: 13.6 MB, less than 7.24% 

    def __init__(self, k: int):
        """
        Initialize your data structure here. Set the size of the queue to be k.
        """
        self._queue = [None] * k #the basic 
        self._capacity = k 
        self._len = 0 
        #The first three categorize as a group, the 4th as the second group
        self._front = 0
        #self._rear is not necessary, because rear = front + length -1

    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
        avail = (self._front + self._len) % (self._capacity)
        self._queue[avail] = value 
        self._len += 1
        return True 

    def deQueue(self) -> bool:
        """
        Delete an element from the circular queue. Return true if the operation is successful.
        """
        if self.isEmpty():
            return False 
        self._queue[self._front] = None #overrode the current node 
        self._front = (self._front+1) % self._capacity 
        self._len -= 1
        return True

    def Front(self) -> int:
        """
        Get the front item from the queue.
        """
        if not self.isEmpty():
            return self._queue[self._front]
        else:
            return -1


    def Rear(self) -> int:
        """
        Get the last item from the queue.
        """
        if not self.isEmpty():
            _rear = (self._front + self._len - 1) % self._capacity
            return self._queue[_rear]
        else:
            return -1


    def isEmpty(self) -> bool:
        """
        Checks whether the circular queue is empty or not.
        """
        return self._len == 0 


    def isFull(self) -> bool:
        """
        Checks whether the circular queue is full or not.
        """
        return self._len == self._capacity 

Дизайн Гудрича очень удобен для чтения с меньшими усилиями.

Тем не менее, при чтении других представленных материалов общепринятой практикой является инициализация self._fornt и self._rear как -1, хотя чтение или запись требуют усилий.

Выдержка из случая, производительность которого выше 98%

def deQueue(self):
    """
    Delete an element from the circular queue. Return true if the operation is successful.
    :rtype: bool
    """
    if self.isEmpty():
        return False 
    self.head = (self.head+1) % self.maxlen
    self.currlen -= 1
    if self.isEmpty(): #have to take care of self.head and self.tail
        self.head = -1
        self.tail = -1

   #another submission which initialize front and rear =-1
    def enQueue(self, value: 'int') -> 'bool':
        """
        Insert an element into the circular queue. Return true if the operation is successful.
        """
        if (self.len == self.capacity): return False

        # To check if full
        #if (self.rear == self.front - 1 or (self.rear == self.capacity - 1 and self.front == 0) )
        if (self.front == -1):
            self.front, self.rear = 0, 0
        elif (self.rear == self.capacity - 1 and self.front != 0):
            # make rear start (case when element was removed from start)
            self.rear = 0
        else:
            self.rear = (self.rear + 1) % self.capacity
        self.data[self.rear] = value
        self.len += 1
        return True

Поскольку python скрывает большинство деталей реализации,

Какое преимущество взять front или rear вместо -1?