problem-solving-with-algorithms-and-data-structure-usingpython(使用python解决算法和数据结构) -- 基本数据结构（一）

栈，队列，deques, 列表是一类数据的容器，它们数据项之间的顺序由添加或删除的顺序决定。

一旦一个数据项被添加，它相对于前后元素一直保持该位置不变。

诸如此类的数据结构被称为线性数据结构。

栈（有时称为“后进先出栈”）是一个项的有序集合，其中添加移除新项总发生在同一端。

这一端通常称为“顶部”。与顶部对应的端称为“底部”。

实际应用：
每个 web 浏览器都有一个返回按钮。当你浏览网页时，这些网页被放置在一个栈中（实际是网页的网址）。

你现在查看的网页在顶部，你第一个查看的网页在底部。如果按‘返回’按钮，将按相反的顺序浏览刚才的页面。

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[-1]
    def size(self):
        return len(self.items)

s = Stack()
print(s.isEmpty())          # True
s.push(4)
s.push(‘dog‘)
print(s.peek())             # dog
s.push(True)
print(s.size())             # 3
print(s.isEmpty())          # False
s.push(8.4)
print(s.pop())              # 8.4
s.pop()
print(s.size())             # 2

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[-1]
    def size(self):
        return len(self.items)


def parChecker(symbolString):
    s = Stack()
    balanced = True
    index = 0
    while index < len(symbolString) and balanced:
        symbol = symbolString[index]
        if symbol == ‘(‘:
            s.push(symbol)
        else:
            if s.isEmpty():
                balanced = False
            else:
                s.pop()
        index += 1
    return balanced and s.isEmpty()

print(parChecker(‘((())()())‘))
print(parChecker(‘()(((()(()())))‘))

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[-1]
    def size(self):
        return len(self.items)

def parChecker(symbolString):
    s = Stack()
    balanced = True
    index = 0
    while index < len(symbolString) and balanced:
        symbol = symbolString[index]
        if symbol in ‘([{‘:
            s.push(symbol)
        else:
            if s.isEmpty():
                balanced = False
            else:
                top = s.pop()
                if not ‘([{‘.index(top) == ‘)]}‘.index(symbol):
                    balanced = False
        index += 1
    return balanced and s.isEmpty()

print(parChecker(‘{({}){}([][])}‘))
print(parChecker(‘[{()]‘))

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[-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(11))
print(divideBy2(42))

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[-1]
    def size(self):
        return len(self.items)

def divideBy2(decNumber,base):
    ‘‘‘
    十进制数转换成任意进制(16以下)
    :param decNumber: 十进制数
    :param base: 要转换成多少进制
    :return: 结果
    ‘‘‘
    digits = ‘0123456789ABCDEF‘         # 假如余数为13，则通过13索引找到D
    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(divideBy2(11,8))
print(divideBy2(42,16))