NOWCODER 剑指offer 构造栈，取最小

top只是取值，不删除；pop取值之后会删除

用Python有点犯规

# -*- coding:utf-8 -*-
class Solution:
    def __init__(self):
        self.stack = []
    def push(self, node):
        # write code here
        self.stack.append(node)
        #return stack
    def pop(self):
        # write code here
        return self.stack.pop()
    def top(self):
        # write code here
        return self.stack[-1]
    def min(self):
        # write code here
        return min(self.stack)