Python3求栈最小元素

[本文出自天外归云的博客园]

思路：入栈时靠辅助栈记住主栈元素中最小的，出栈时一直pop主栈元素直到辅助栈栈顶元素出现。

代码如下（定义栈、超级栈）：

class Stack(object):
    def __init__(self):
        self.items = []

    def push(self, ele):
        self.items.append(ele)

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

    def pop(self):
        top = self.items.pop()
        return top

class SuperStack(Stack):
    def __init__(self):
        self.stack = Stack()
        self.temp = Stack()

    # 入栈的时候把最小的元素放到辅助栈栈顶
    def push(self, ele):
        if self.temp.items == []:
            self.temp.push(ele)
        elif ele < self.temp.peek():
            self.temp.push(ele)
        self.stack.push(ele)

    # 出栈的时候一直pop直到等于辅助栈栈顶元素的元素出现
    def pop(self):
        min = self.temp.peek()
        while True:
            if self.stack.peek() != min:
                print(f'POP:{self.stack.pop()}')
            else:
                print(f'MIN:{self.stack.peek()}')
                break

if __name__ == '__main__':
    ss = SuperStack()
    ss.push(22)
    ss.push(3)
    ss.push(33)
    ss.push(4)
    ss.push(55)
    ss.push(12)
    ss.push(13)
    ss.push(16)
    ss.pop()

运行结果：