python-数据结构代码 队列

 

from pythonds.basic.queue import Queue
import random
def hotPotato(namelist,num):
    simqueue = Queue()
    for name in namelist:
        simqueue.enqueue(name)
    while simqueue.size()>1:
        for i in range(num):
            simqueue.enqueue(simqueue.dequeue())
        simqueue.dequeue()
    return simqueue.dequeue()
    
class Queue:
    def __init__(self):
        self.items = []

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

    def enqueue(self, item):
        self.items.insert(0,item)

    def dequeue(self):
        return self.items.pop()

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

class Printer:
    def __init__(self,ppm):
        self.pagerate=ppm
        self.currentTask = None
        self.timeRemaining=0
    def tick(self):
        if self.currentTask!= None:
            self.timeRemaining=self.timeRemaining-1
            if self.timeRemaining <=0:
                self.currentTask=None
    def busy(self):
        if self.currentTask!=None:
            return True
        else:
            return False
    def startNext(self,newtask):
        self.currentTask=newtask
        self.timeRemaining=newtask.getPages()*60/self.pagerate

class Task:
    def __init__(self,time):
        self.timestamp=time
        self.pages=random.randrange(1,21)
    def getStamp(self):
        return self.timestamp
    def getPages(self):
        return self.pages
    def waitTime(self,currenttime):
        return currenttime-self.timestamp

def simulation(numSeconds,pagesPerMinute):
    labprinter=Printer(pagesPerMinute)
    printQueue=Queue()
    waitingtimes=[]
    for currentSecond in range(numSeconds):
        if newPrintTask():
            task=Task(currentSecond)
            printQueue.enqueue(task)
        if (not labprinter.busy()) and (not printQueue.isEmpty()):
            nexttask = printQueue.dequeue()
            waitingtimes.append(nexttask.waitTime(currentSecond))
            labprinter.startNext(nexttask)
        labprinter.tick()

    averageWait=sum(waitingtimes)/len(waitingtimes)
    print("Average Wait %6.2f secs %3d tasks remaining."%(averageWait,printQueue.size()))

def newPrintTask():
    num=random.randrange(1,181)
    if num==180:
        return True
    else:
        return False
for i in range(10):
    simulation(3600,5)