python学习之双端队列和链表实现队列

Posted 2021-07-14 今夜月色很美

一、使用数组实现双端队列

class Deque:
    def __init__(self):
        self.list = list()

    def addFront(self, item):
        self.list.insert(0, item)

    def addRear(self, item):
        self.list.append(item)

    def removeFront(self):
        return self.list.pop(0)

    def removeLast(self):
        return self.list.pop()

    def size(self):
        return len(self.list)

    def isEmpty(self):
        return self.list == []

    def __str__(self):
        return self.list.__str__()

二、使用链表实现队列

1.定义链表节点对象node

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

    def getData(self):
        return self.data

    def getNext(self):
        return self.next

    def setData(self, data):
        self.data = data

    def setNext(self, node):
        self.next = node

2.使用链表实现队列

from node import Node

class LinkedQueue:
    def __init__(self):
        self.head = self.last = Node(None)

    def offer(self, data):
        newNode = Node(data)
        newNode.setNext(None)
        self.last.setNext(newNode)
        self.last = self.last.getNext()

    def poll(self):
        firstNode = self.head.getNext()
        if firstNode == None:
            print("队列是空的。")
        else:
            self.head.setNext(self.head.getNext().getNext())
            return firstNode.getData()

3.测试

from linked_queue import LinkedQueue

queue = LinkedQueue()
queue.offer(11)
queue.offer(22)
queue.offer(33)
queue.offer(44)
queue.offer(55)
print(queue.poll())
print(queue.poll())
print(queue.poll())
print(queue.poll())
print(queue.poll())
print(queue.poll())
print(queue.poll())