题解 | #包含min函数的栈#

# -*- coding:utf-8 -*-
class Solution:

    stack = []
    stack_min = []

    def push(self, node):
        # write code here
        # print(node)
        #普通栈栈顶入栈
        self.stack.append(node)
        if not self.stack_min:
            # 添加最小栈栈顶元素
            self.stack_min.append(node)
        else:
            # 最小栈栈顶元素更新
            if node <= self.stack_min[-1]:
                self.stack_min.append(node)

    def pop(self):
        # write code here
        length = len(self.stack)
        length2 = len(self.stack_min)
        # 更新栈顶元素
        x = self.stack[-1]
        self.stack = self.stack[: length - 1]
        # 最小栈栈顶元素出栈
        if x == self.stack_min[-1]:
            self.stack_min = self.stack_min[: length2 - 1]
        return x

    def top(self):
        # write code here
        x = self.stack[-1]
        return x

    def min(self):
        # write code here
        return self.stack_min[-1]