题目描述
定义栈的数据结构,请在该类型中实现一个能够得到栈中所含最小元素的min函数(时间复杂度应为O(1))。
# -*- coding:utf-8 -*- class Solution: def __init__(self): self.stack = [] self.min_stack = [] def push(self, node): # write code here self.stack.append(node) if not self.min_stack or node <= self.min_stack[-1]: self.min_stack.append(node) else: self.min_stack.append(self.min_stack[-1]) def pop(self): # write code here #if not self.stack: self.stack.pop() self.min_stack.pop() def top(self): # write code here return self.stack[-1] def min(self): # write code here return self.min_stack[-1]