CF987B - High School: Become Human
Year 2118. Androids are in mass production for decades now, and they do all the work for humans. But androids have to go to school to be able to solve creative tasks. Just like humans before.
It turns out that high school struggles are not gone. If someone is not like others, he is bullied. Vasya-8800 is an economy-class android which is produced by a little-known company. His design is not perfect, his characteristics also could be better. So he is bullied by other androids.
One of the popular pranks on Vasya is to force him to compare xy with yx. Other androids can do it in milliseconds while Vasya's memory is too small to store such big numbers.
Please help Vasya! Write a fast program to compare xyxy with yx for Vasya, maybe then other androids will respect him.
Input
On the only line of input there are two integers x and y (1≤x,y≤109).
Output
If xy<yx, then print '<' (without quotes). If xy>yx, then print '>' (without quotes). If xy=yx, then print '=' (without quotes).
Examples
5 8
>
10 3
<
6 6
=
Note
In the first example 5 8=5⋅5⋅5⋅5⋅5⋅5⋅5⋅5=390625, and 85=8⋅8⋅8⋅8⋅8=32768. So you should print '>'.
In the second example 10 3=1000<3 10=59049.
In the third example 6 6=46656=6 6.
这道题,看题意首先想到快速幂,再看数据范围,显然会炸,那么最简单粗暴的方法就是,比较 x ^ y 与 y ^ x 的大小关系。(如此简洁明了的题面 >_<)
我们要先在两式旁取对数,就是比较 ln x ^ y 与 ln y ^ x 的大小关系,先假设左式小于右式:(前方高能,请注意)
ln x ^ y < ln y & x; 即 y * ln x < x * lny;
所以 ln x / x < ln y / y;
那么通过归纳我们可以设 f (n) = ln n / n;
取这个函数的导数,即 f'(n) = ( ln n - 1 )/ n ^ 2;
那么当 f'(n)> 0 时, ln n > 1, 所以当 x, y > e (因为是整数,相当于大于等于3)时, 若 x > y, 则 x ^ y < y ^ x;
证明完成之后,我们就可以知道,当给出的 x , y 大于 3 的时候,只需要判断 x 和 y 的大小关系即可,其他的只要特判就可以了
#include<bits/stdc++.h>
using namespace std;
int main()
{
int x,y,i;
cin>>x>>y;
if(x == y){
cout<<"="<<endl;
return 0;
}
else{
if(x == 1){
cout<<"<";
return 0;
}
if(y == 1){
cout<<">";
return 0;
}
int h = max(x,y);
if(h <= 4){
long long sum1 = 1,sum2 = 1;
for(i = 1; i <= y; i++){
sum1 *= x;
}
for(i = 1; i <= x; i++){
sum2 *= y;
}
if(sum1 < sum2){
cout<<"<";
}
else if(sum1 > sum2){
cout<<">";
}
else{
cout<<"=";
}
}
else{
if(x > y){
cout<<"<";
}
else{
cout<<">";
}
}
}
return 0;
}
CF987B - High School: Become Human的更多相关文章
- CF987B High School: Become Human 数学
题意翻译 题目大意 输入一个 xxx ,一个 yyy ,求是 xyx^yxy 大还是 yxy^xyx 大. (1≤x,y≤109)(1≤x,y≤10^9)(1≤x,y≤109) 输入输出格式 输入格式 ...
- Human and AI's future (reverie)
However, I do notice that to make the dark situation happen, it doesn't require the topleft matrix t ...
- Human Gene Functions
Human Gene Functions Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 18053 Accepted: 1004 ...
- PacBio & BioNano (Assembly and diploid architecture of an individual human genome via single-molecule technologies)
Assembly and diploid architecture of an individual human genome via single-molecule technologies 文章链 ...
- POJ 1080 Human Gene Functions -- 动态规划(最长公共子序列)
题目地址:http://poj.org/problem?id=1080 Description It is well known that a human gene can be considered ...
- APP-PER-50022: Oracle Human Resources could not retrieve a value for the User Type profile option.
Symptoms ----------------------- AP > Setup > Organizations Show Error tips: APP-PER-50022: Or ...
- Unity3d 屏幕空间人体皮肤知觉渲染&次表面散射Screen-Space Perceptual Rendering & Subsurface Scattering of Human Skin
之前的人皮渲染相关 前篇1:unity3d Human skin real time rendering 真实模拟人皮实时渲染 前篇2:unity3d Human skin real time ren ...
- 【译】iOS人性化界面指南(iOS Human Interface Guidelines)(一)
1. 引言1.1 译者自述 我是一个表达能力一般的开发员,不管是书面表达,还是语言表达.在很早以前其实就有通过写博客锻炼这方面能力的想法,但水平有限实在没有什么拿得出手的东西分享.自2015年7月以来 ...
- [文学阅读] METEOR: An Automatic Metric for MT Evaluation with Improved Correlation with Human Judgments
METEOR: An Automatic Metric for MT Evaluation with Improved Correlation with Human Judgments Satanje ...
随机推荐
- C语言 内存管理(转)
转自 https://blog.csdn.net/u011616739/article/details/61621815 C语言 内存管理 1.内存分区 C源代码进过预处理.编译.汇编和链接4步生成 ...
- [Leetcode] 01 Matrix
问题: https://leetcode.com/problems/01-matrix/#/description 基本思路:广度优先遍历,根据所有最短距离为N的格找到所有距离为N+1的格,直到所有的 ...
- KAGGLE竟赛
KAGGLE竟赛 关于kaggle的竟赛规则我们勇闯组做出了一些说明,大家可以借鉴一下如何参加kaggle,参加kaggle大赛的一些注意事项,自己参加一些项目,一定会使你的知识量得到质的提升 这是链 ...
- JSON字符串与Map互转
//一.map转为json字符串 public static String map2jsonstr(Map<String,?> map){ return JSONObject.toJSON ...
- Python 数据分析5
数据规整化 清理 转换 合并 重塑 数据库风格的DataFrame合并 pd.merge(df1, df2) # 默认会将重叠列的列名当作键,最好显式的指定下,另外merge默认是使用的inner j ...
- zip4j压缩
使用的jar包:zip4j_1.3.2.jar 基本功能: 针对ZIP压缩文件创建.添加.分卷.更新和移除文件 (读写有密码保护的Zip文件) (支持AES 128/256算法加密) (支持标准Zip ...
- mysql登录报错“Access denied for user 'root'@'localhost' (using password: YES”)的处理方法
环境 CentosOS 6.5 ,已安装mysql 情景 root密码忘记,使用普通用户无法登录 解决 问题一 无法使用mysql命令 参考文章:https://www.cnblogs.com/com ...
- EntityFramework6之原生SQL
原文:https://www.cnblogs.com/wujingtao/p/5412329.html 用EF执行SQL又比ADO.NET方便,特别是在执行查询语句的时候,EF会把查询到的数据自动保存 ...
- Django --- 单表的增删改查
- computed计算属性
在computed中,可以定义一些属性,这些属性 叫做计算属性.计算属性的本质是一个方法,只不过我们在使用的时候,把他们的名称当做属性来使用,并不会吧计算属性当做方法去调用.与methods平级. / ...