注意

队列的创建方式，需要导入包

常见的操作：添加元素，移除元素，读取元素以及获取队列长度

队列的约束条件是：先进先出（FIFO）, 队尾添加（类list.pop()）队头移除

代码实现

-- codeing = utf-8 --
# @Time : 2/6/2021 4:11 PM
# @Autor : Caesar
# @File : queue.py
# @ Software : PyCharm
_”””队尾添加|3|2|1|队头移除”””
_from collections import deque

Create a queue
queue = deque()

Add an element
# Time complexity : O(1)
queue.append(1)
queue.append(2)
queue.append(3)
# [1, 2, 3]
print(queue)

Get an element from the head of queue
# Time complexity: O(1)
tempt1 = queue[0]
print(tempt1)

Remove an element from the tail of queue
# Time complexity : O(1)
# 移除的操作是有返回值的，而列表中的移除:list.pop()是默认删除，不会以值传递的形式输出结果
tempt2 = queue.popleft()
print(tempt2)
# [2, 3]

Queue is empty?
# Time complexity: O(1)
length = len(queue)
print(length)

Time complexity: O(N)
while len(queue) != 0:
temp = queue.popleft()
print(temp)