剑指offer-包含min函数的栈20

class Solution:
    def __init__(self):
        self.stack=[]
        self.minj=0
        
    def push(self, node):
        # write code here
        self.stack.append(node)
        if len(self.stack)==0:
            self.minj=node
        else:
            self.minj=min(self.stack)
        
    def pop(self):
        # write code here
        self.stack.pop(-1)
        self.minj=min(self.stack)
    def top(self):
        # write code here
        self.stack[len(self.stack)-1]
    def min(self):
        # write code here
        return self.minj