python 栈和队列

class Stack:
    def __init__(self):
        self.items = []
    def isEmpty(self):
        return self.items == []
    def push(self,item):
        self.items.append(item)
    def pop(self):
        return self.items.pop()
    def peek(self):
        return self.items[len(self.items)-1]
    def size(self):
        return len(self.items)
def divideBy2(decNumber):
    remstack = Stack()
    while decNumber > 0:
        rem = decNumber % 2
        remstack.push(rem)
        decNumber = decNumber // 2
    binString =  ""
    while not remstack.isEmpty():
        binString = binString + str(remstack.pop())
    return binString
# print(divideBy2(42))
def baseConverter(decNumber,base):
    digits = "0123456789ABCDEF"
    remstack = Stack()
    while decNumber > 0:
        rem = decNumber % base
        remstack.push(rem)
        decNumber = decNumber // base
    newString = ""
    while not remstack.isEmpty():
        newString = newString + digits[remstack.pop()]
    return newString
# print(baseConverter(25,2))
# print(baseConverter(25,16))
def infixToPostfix(infixexpr):
    prec = {}
    prec["*"] = 3
    prec["/"] = 3
    prec["+"] = 2
    prec["-"] = 2
    prec["("] = 1
    opStack = Stack()
    postfixList = []
    tokenList = infixexpr.split()
    for token in tokenList:
        if token in "ABCDEFGHIJKLMNOPQRSTUVWXYZ" or token in "0123456789":
            postfixList.append(token)
        elif token == '(':
            opStack.push(token)
        elif token == ')':
            topToken = opStack.pop()
            while topToken != '(':
                postfixList.append(topToken)
                topToken = opStack.pop()
        else:
            while (not opStack.isEmpty()) and 
                    (prec[opStack.peek()] >= prec[token]):
                postfixList.append(opStack.pop())
            opStack.push(token)
    while not opStack.isEmpty():
        postfixList.append(opStack.pop())
    return " ".join(postfixList)

def postfixEval(postfixExpr):
    operandStack = Stack()
    tokenList = postfixExpr.split()

    for token in tokenList:
        if token in "0123456789":
            operandStack.push(int(token))
        else:
            operand2 = operandStack.pop()
            operand1 = operandStack.pop()
            result = doMath(token,operand1,operand2)
            operandStack.push(result)
    return operandStack.pop()

def doMath(op, op1, op2):
    if op == "*":
        return op1 * op2
    elif op == "/":
        return op1 / op2
    elif op == "+":
        return op1 + op2
    else:
        return op1 - op2

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)

def hotPotato(namelist, num):
    simqueue = Queue()
    for name in namelist:
        simqueue.enqueue(name)

    while simqueue.size() > 1:
        for i in range(num):
            print(i)
            print(simqueue.enqueue(simqueue.dequeue()))

        simqueue.dequeue()

    return simqueue.dequeue()

print(hotPotato(["Bill","David","Susan","Jan e","Kent","Brad"],7))