python 穷举法 算24点（史上最简短代码）
本来想用回溯法实现 算24点。题目都拟好了，就是《python 回溯法 子集树模板 系列 —— 7、24点》。无奈想了一天，没有头绪。只好改用暴力穷举法。
思路说明
根据四个数，三个运算符，构造三种中缀表达式，遍历，计算每一种可能
显然可能的形式不止三种。但是，其它的形式要么得不到24点，要么在加、乘意义下可以转化为这三种形式的表达式！
使用内置的eval函数计算中缀表达式，使得代码变得非常简洁！
完整代码
# 作者：hhh5460
# 时间：2017年6月3日
import itertools
def twentyfour(cards):
'''史上最短计算24点代码'''
for nums in itertools.permutations(cards): # 四个数
for ops in itertools.product('+-*/', repeat=3): # 三个运算符（可重复！）
# 构造三种中缀表达式 (bsd)
bds1 = '({0}{4}{1}){5}({2}{6}{3})'.format(*nums, *ops) # (a+b)*(c-d)
bds2 = '(({0}{4}{1}){5}{2}){6}{3}'.format(*nums, *ops) # (a+b)*c-d
bds3 = '{0}{4}({1}{5}({2}{6}{3}))'.format(*nums, *ops) # a/(b-(c/d))
for bds in [bds1, bds2, bds3]: # 遍历
try:
if abs(eval(bds) - 24.0) < 1e-10: # eval函数
return bds
except ZeroDivisionError: # 零除错误！
continue
return 'Not found!'
# 测试
# 数据来源：http://www.cnblogs.com/grenet/archive/2013/02/28/2936965.html
cards =[[1,1,1,8],
[1,1,2,6],
[1,1,2,7],
[1,1,2,8],
[1,1,2,9],
[1,1,2,10],
[1,1,3,4],
[1,1,3,5],
[1,1,3,6],
[1,1,3,7],
[1,1,3,8],
[1,1,3,9],
[1,1,3,10],
[1,1,4,4],
[1,1,4,5],
[1,1,4,6],
[1,1,4,7],
[1,1,4,8],
[1,1,4,9],
[1,1,4,10],
[1,1,5,5],
[1,1,5,6],
[1,1,5,7],
[1,1,5,8],
[1,1,6,6],
[1,1,6,8],
[1,1,6,9],
[1,1,7,10],
[1,1,8,8],
[1,2,2,4],
[1,2,2,5],
[1,2,2,6],
[1,2,2,7],
[1,2,2,8],
[1,2,2,9],
[1,2,2,10],
[1,2,3,3],
[1,2,3,4],
[1,2,3,5],
[1,2,3,6],
[1,2,3,7],
[1,2,3,8],
[1,2,3,9],
[1,2,3,10],
[1,2,4,4],
[1,2,4,5],
[1,2,4,6],
[1,2,4,7],
[1,2,4,8],
[1,2,4,9],
[1,2,4,10],
[1,2,5,5],
[1,2,5,6],
[1,2,5,7],
[1,2,5,8],
[1,2,5,9],
[1,2,5,10],
[1,2,6,6],
[1,2,6,7],
[1,2,6,8],
[1,2,6,9],
[1,2,6,10],
[1,2,7,7],
[1,2,7,8],
[1,2,7,9],
[1,2,7,10],
[1,2,8,8],
[1,2,8,9],
[1,2,8,10],
[1,3,3,3],
[1,3,3,4],
[1,3,3,5],
[1,3,3,6],
[1,3,3,7],
[1,3,3,8],
[1,3,3,9],
[1,3,3,10],
[1,3,4,4],
[1,3,4,5],
[1,3,4,6],
[1,3,4,7],
[1,3,4,8],
[1,3,4,9],
[1,3,4,10],
[1,3,5,6],
[1,3,5,7],
[1,3,5,8],
[1,3,5,9],
[1,3,5,10],
[1,3,6,6],
[1,3,6,7],
[1,3,6,8],
[1,3,6,9],
[1,3,6,10],
[1,3,7,7],
[1,3,7,8],
[1,3,7,9],
[1,3,7,10],
[1,3,8,8],
[1,3,8,9],
[1,3,8,10],
[1,3,9,9],
[1,3,9,10],
[1,3,10,10],
[1,4,4,4],
[1,4,4,5],
[1,4,4,6],
[1,4,4,7],
[1,4,4,8],
[1,4,4,9],
[1,4,4,10],
[1,4,5,5],
[1,4,5,6],
[1,4,5,7],
[1,4,5,8],
[1,4,5,9],
[1,4,5,10],
[1,4,6,6],
[1,4,6,7],
[1,4,6,8],
[1,4,6,9],
[1,4,6,10],
[1,4,7,7],
[1,4,7,8],
[1,4,7,9],
[1,4,8,8],
[1,4,8,9],
[1,4,9,10],
[1,4,10,10],
[1,5,5,5],
[1,5,5,6],
[1,5,5,9],
[1,5,5,10],
[1,5,6,6],
[1,5,6,7],
[1,5,6,8],
[1,5,6,9],
[1,5,6,10],
[1,5,7,8],
[1,5,7,9],
[1,5,7,10],
[1,5,8,8],
[1,5,8,9],
[1,5,8,10],
[1,5,9,9],
[1,5,9,10],
[1,5,10,10],
[1,6,6,6],
[1,6,6,8],
[1,6,6,9],
[1,6,6,10],
[1,6,7,9],
[1,6,7,10],
[1,6,8,8],
[1,6,8,9],
[1,6,8,10],
[1,6,9,9],
[1,6,9,10],
[1,7,7,9],
[1,7,7,10],
[1,7,8,8],
[1,7,8,9],
[1,7,8,10],
[1,7,9,9],
[1,7,9,10],
[1,8,8,8],
[1,8,8,9],
[1,8,8,10],
[2,2,2,3],
[2,2,2,4],
[2,2,2,5],
[2,2,2,7],
[2,2,2,8],
[2,2,2,9],
[2,2,2,10],
[2,2,3,3],
[2,2,3,4],
[2,2,3,5],
[2,2,3,6],
[2,2,3,7],
[2,2,3,8],
[2,2,3,9],
[2,2,3,10],
[2,2,4,4],
[2,2,4,5],
[2,2,4,6],
[2,2,4,7],
[2,2,4,8],
[2,2,4,9],
[2,2,4,10],
[2,2,5,5],
[2,2,5,6],
[2,2,5,7],
[2,2,5,8],
[2,2,5,9],
[2,2,5,10],
[2,2,6,6],
[2,2,6,7],
[2,2,6,8],
[2,2,6,9],
[2,2,6,10],
[2,2,7,7],
[2,2,7,8],
[2,2,7,10],
[2,2,8,8],
[2,2,8,9],
[2,2,8,10],
[2,2,9,10],
[2,2,10,10],
[2,3,3,3],
[2,3,3,5],
[2,3,3,6],
[2,3,3,7],
[2,3,3,8],
[2,3,3,9],
[2,3,3,10],
[2,3,4,4],
[2,3,4,5],
[2,3,4,6],
[2,3,4,7],
[2,3,4,8],
[2,3,4,9],
[2,3,4,10],
[2,3,5,5],
[2,3,5,6],
[2,3,5,7],
[2,3,5,8],
[2,3,5,9],
[2,3,5,10],
[2,3,6,6],
[2,3,6,7],
[2,3,6,8],
[2,3,6,9],
[2,3,6,10],
[2,3,7,7],
[2,3,7,8],
[2,3,7,9],
[2,3,7,10],
[2,3,8,8],
[2,3,8,9],
[2,3,8,10],
[2,3,9,9],
[2,3,9,10],
[2,3,10,10],
[2,4,4,4],
[2,4,4,5],
[2,4,4,6],
[2,4,4,7],
[2,4,4,8],
[2,4,4,9],
[2,4,4,10],
[2,4,5,5],
[2,4,5,6],
[2,4,5,7],
[2,4,5,8],
[2,4,5,9],
[2,4,5,10],
[2,4,6,6],
[2,4,6,7],
[2,4,6,8],
[2,4,6,9],
[2,4,6,10],
[2,4,7,7],
[2,4,7,8],
[2,4,7,9],
[2,4,7,10],
[2,4,8,8],
[2,4,8,9],
[2,4,8,10],
[2,4,9,9],
[2,4,9,10],
[2,4,10,10],
[2,5,5,7],
[2,5,5,8],
[2,5,5,9],
[2,5,5,10],
[2,5,6,6],
[2,5,6,7],
[2,5,6,8],
[2,5,6,9],
[2,5,6,10],
[2,5,7,7],
[2,5,7,8],
[2,5,7,9],
[2,5,7,10],
[2,5,8,8],
[2,5,8,9],
[2,5,8,10],
[2,5,9,10],
[2,5,10,10],
[2,6,6,6],
[2,6,6,7],
[2,6,6,8],
[2,6,6,9],
[2,6,6,10],
[2,6,7,8],
[2,6,7,9],
[2,6,7,10],
[2,6,8,8],
[2,6,8,9],
[2,6,8,10],
[2,6,9,9],
[2,6,9,10],
[2,6,10,10],
[2,7,7,8],
[2,7,7,10],
[2,7,8,8],
[2,7,8,9],
[2,7,9,10],
[2,7,10,10],
[2,8,8,8],
[2,8,8,9],
[2,8,8,10],
[2,8,9,9],
[2,8,9,10],
[2,8,10,10],
[2,9,10,10],
[3,3,3,3],
[3,3,3,4],
[3,3,3,5],
[3,3,3,6],
[3,3,3,7],
[3,3,3,8],
[3,3,3,9],
[3,3,3,10],
[3,3,4,4],
[3,3,4,5],
[3,3,4,6],
[3,3,4,7],
[3,3,4,8],
[3,3,4,9],
[3,3,5,5],
[3,3,5,6],
[3,3,5,7],
[3,3,5,9],
[3,3,5,10],
[3,3,6,6],
[3,3,6,7],
[3,3,6,8],
[3,3,6,9],
[3,3,6,10],
[3,3,7,7],
[3,3,7,8],
[3,3,7,9],
[3,3,8,8],
[3,3,8,9],
[3,3,8,10],
[3,3,9,9],
[3,3,9,10],
[3,4,4,4],
[3,4,4,5],
[3,4,4,6],
[3,4,4,7],
[3,4,4,8],
[3,4,4,9],
[3,4,4,10],
[3,4,5,5],
[3,4,5,6],
[3,4,5,7],
[3,4,5,8],
[3,4,5,9],
[3,4,5,10],
[3,4,6,6],
[3,4,6,8],
[3,4,6,9],
[3,4,6,10],
[3,4,7,7],
[3,4,7,8],
[3,4,7,9],
[3,4,7,10],
[3,4,8,9],
[3,4,8,10],
[3,4,9,9],
[3,4,10,10],
[3,5,5,6],
[3,5,5,7],
[3,5,5,8],
[3,5,5,9],
[3,5,6,6],
[3,5,6,7],
[3,5,6,8],
[3,5,6,9],
[3,5,6,10],
[3,5,7,8],
[3,5,7,9],
[3,5,7,10],
[3,5,8,8],
[3,5,8,9],
[3,5,9,9],
[3,5,9,10],
[3,5,10,10],
[3,6,6,6],
[3,6,6,7],
[3,6,6,8],
[3,6,6,9],
[3,6,6,10],
[3,6,7,7],
[3,6,7,8],
[3,6,7,9],
[3,6,7,10],
[3,6,8,8],
[3,6,8,9],
[3,6,8,10],
[3,6,9,9],
[3,6,9,10],
[3,6,10,10],
[3,7,7,7],
[3,7,7,8],
[3,7,7,9],
[3,7,7,10],
[3,7,8,8],
[3,7,8,9],
[3,7,9,9],
[3,7,9,10],
[3,7,10,10],
[3,8,8,8],
[3,8,8,9],
[3,8,8,10],
[3,8,9,9],
[3,8,9,10],
[3,8,10,10],
[3,9,9,9],
[3,9,9,10],
[3,9,10,10],
[4,4,4,4],
[4,4,4,5],
[4,4,4,6],
[4,4,4,7],
[4,4,4,8],
[4,4,4,9],
[4,4,4,10],
[4,4,5,5],
[4,4,5,6],
[4,4,5,7],
[4,4,5,8],
[4,4,5,10],
[4,4,6,8],
[4,4,6,9],
[4,4,6,10],
[4,4,7,7],
[4,4,7,8],
[4,4,7,9],
[4,4,7,10],
[4,4,8,8],
[4,4,8,9],
[4,4,8,10],
[4,4,10,10],
[4,5,5,5],
[4,5,5,6],
[4,5,5,7],
[4,5,5,8],
[4,5,5,9],
[4,5,5,10],
[4,5,6,6],
[4,5,6,7],
[4,5,6,8],
[4,5,6,9],
[4,5,6,10],
[4,5,7,7],
[4,5,7,8],
[4,5,7,9],
[4,5,7,10],
[4,5,8,8],
[4,5,8,9],
[4,5,8,10],
[4,5,9,9],
[4,5,9,10],
[4,5,10,10],
[4,6,6,6],
[4,6,6,7],
[4,6,6,8],
[4,6,6,9],
[4,6,6,10],
[4,6,7,7],
[4,6,7,8],
[4,6,7,9],
[4,6,7,10],
[4,6,8,8],
[4,6,8,9],
[4,6,8,10],
[4,6,9,9],
[4,6,9,10],
[4,6,10,10],
[4,7,7,7],
[4,7,7,8],
[4,7,8,8],
[4,7,8,9],
[4,7,8,10],
[4,7,9,9],
[4,7,9,10],
[4,7,10,10],
[4,8,8,8],
[4,8,8,9],
[4,8,8,10],
[4,8,9,9],
[4,8,9,10],
[4,8,10,10],
[4,9,9,10],
[5,5,5,5],
[5,5,5,6],
[5,5,5,9],
[5,5,6,6],
[5,5,6,7],
[5,5,6,8],
[5,5,7,7],
[5,5,7,8],
[5,5,7,10],
[5,5,8,8],
[5,5,8,9],
[5,5,8,10],
[5,5,9,9],
[5,5,9,10],
[5,5,10,10],
[5,6,6,6],
[5,6,6,7],
[5,6,6,8],
[5,6,6,9],
[5,6,6,10],
[5,6,7,7],
[5,6,7,8],
[5,6,7,9],
[5,6,8,8],
[5,6,8,9],
[5,6,8,10],
[5,6,9,9],
[5,6,9,10],
[5,6,10,10],
[5,7,7,9],
[5,7,7,10],
[5,7,8,8],
[5,7,8,9],
[5,7,8,10],
[5,7,9,10],
[5,7,10,10],
[5,8,8,8],
[5,8,8,9],
[5,8,8,10],
[5,9,10,10],
[6,6,6,6],
[6,6,6,8],
[6,6,6,9],
[6,6,6,10],
[6,6,7,9],
[6,6,7,10],
[6,6,8,8],
[6,6,8,9],
[6,6,8,10],
[6,6,9,10],
[6,7,7,10],
[6,7,8,9],
[6,7,8,10],
[6,7,9,9],
[6,7,10,10],
[6,8,8,8],
[6,8,8,9],
[6,8,8,10],
[6,8,9,9],
[6,8,9,10],
[6,9,9,10],
[6,10,10,10],
[7,7,9,10],
[7,8,8,9],
[7,8,8,10],
[7,8,9,10],
[7,8,10,10],
[8,8,8,10]]
for card in cards:
print(twentyfour(card))
以上数据全都pass，图我就不截了
python 穷举法 算24点（史上最简短代码）的更多相关文章
- python穷举法解数独
总体思路 : 数独九行九列,一个list装一行,也就需要一个嵌套两层的list 初始会有很多数字,我可不想一个一个赋值 那就要想办法偷懒啦 然后再是穷举,如何科学的穷举 第一部分:录入 某在线数独网站 ...
- C#4 for循环 迭代法 穷举法应用
for()循环. 四要素: 初始条件,循环条件,状态改变,循环体. 执行过程: 初始条件--循环条件--循环体--状态改变--循环条件.... 注意:for的小括号里面分号隔开,for的小括号后不要加 ...
- C# for 循环 迭代法 穷举法
for()循环. 四要素: 初始条件,循环条件,状态改变,循环体. 执行过程: 初始条件--循环条件--循环体--状态改变--循环条件.... 注意:for的小括号里面分号隔开,for的小括号后不要加 ...
- 穷举法、for循环、函数、作用域、斐波那契数
1.穷举法 枚举所有可能性,直到得到正确的答案或者尝试完所有值. 穷举法经常是解决问题的最实用的方法,它实现起来热别容易,并且易于理解. 2.for循环 for语句一般形式如下: for variab ...
- 作业：for循环，迭代法和穷举法
for()循环 四要素:初始条件,循环条件,状态改变,循环体. 执行过程:初始条件--循环条件--循环体 ...
- for循环语句以及迭代法和穷举法
循环语句: 四要素:初始条件,循环条件,状态改变,循环体 for(初始条件;循环条件;状态改变){ //循环体} 案例1:打印等腰直角三角形和菱形 左上三角 static void Main(stri ...
- 【2-24】for循环嵌套，跳转语句，异常语句，穷举法、迭代法
For循环嵌套与if嵌套相似,是在for中再套for,其结构如下: For(;;) { For(;;){} }经典题型为打印星星例: Console.Write("请输入一个奇数:" ...
- C# 异常语句 跳转语句 while循环 穷举法 迭代法
一 异常语句 ♦ try.....catch....finally 结构形式 try{ 可能会出错的代码语句 如果这里出错了,那么不会在继续下面的代码,而是直接进入catch中处理异常}catc ...
- 基本算法思想之穷举法（C++语言描述）
穷举算法(Exhaustive Attack method)是最简单的一种算法,其依赖于计算机的强大计算能力来穷尽每一种可能性,从而达到求解问题的目的.穷举算法效率不高,但是适应于一些没有规律可循的场 ...
随机推荐
- 稳聘App设计图分享
摘要||潜心学习,无限开源,我是鸟窝,一只憨厚的鸟,联系我加微信:jkxx123321 很早期就想筹划上线一款招聘类App,一拖再拖,先做还没有上线. 下面的设计原图,为我UI徒弟所做,在此,表示万分 ...
- Python+Selenium笔记（六）：元素定位
(一) 前言 Web应用以及包含超文本标记语言(HTML).层叠样式表(CSS).JS脚本的WEB页面,基于用户的操作(例如点击提交按钮),浏览器向WEB服务器发送请求,WEB服务器响应请求,返 ...
- Java中的StringTokenizer类的使用方法
StringTokenizer是字符串分隔解析类型,属于:java.util包. 1.StringTokenizer的构造函数 StringTokenizer(String str):构造一个用来解析 ...
- 多个div中的label标签对齐
这是之前的页面效果: 添加红色部门的代码后: <head> <meta name="viewport" content="width=device-wi ...
- Oracle Dynamic Performance Views Version 12.2.0.1
Oracle Dynamic Performance ViewsVersion 12.2.0.1 https://www.morganslibrary.org/reference/dyn_perf_v ...
- python基础学习24----使用pymysql连接mysql
使用pymysql连接mysql 安装pymysql pymysql安装可以通过两种方式 使用pip安装 首先简单说一下pip的使用方法 获取帮助 pip --help 升级 pip pip inst ...
- 乘风破浪：LeetCode真题_025_Reverse Nodes in k-Group
乘风破浪:LeetCode真题_025_Reverse Nodes in k-Group 一.前言 将一个链表按照一定的长度切成几部分,然后每部分进行翻转以后再拼接成一个链表是比较困难的,但是这也能锻 ...
- 每年有20万人进军IT行业，为何还会人才短缺？
众所周知,IT行业是个高薪行业,也是很多人的梦想职业,在全球最缺人的十大行业中IT行业居首位. 但是现在很多人都有一个疑问: 几乎每所大学里都有计算机技术相关专业,再加上IT培训机构的输出,每年培养出 ...
- python爬虫（三）
webdriver Selenium是ThroughtWorks公司开发的一套Web自动化测试工具.它分为三个组件:Selenium IDE,Selenium RC (Remote Control), ...
- 3130: [Sdoi2013]费用流
Description Alice和Bob在图论课程上学习了最大流和最小费用最大流的相关知识. 最大流问题:给定一张有向图表示运输网络,一个源点S和一个汇点T,每条边都有最大流量.一个合法的网络流方案 ...