Educational Codeforces Round 39 Editorial B(Euclid算法,连续-=与%=的效率)
You have two variables a and b. Consider the following sequence of actions performed with these variables:
- If a = 0 or b = 0, end the process. Otherwise, go to step 2;
- If a ≥ 2·b, then set the value of a to a - 2·b, and repeat step 1. Otherwise, go to step 3;
- If b ≥ 2·a, then set the value of b to b - 2·a, and repeat step 1. Otherwise, end the process.
Initially the values of a and b are positive integers, and so the process will be finite.
You have to determine the values of a and b after the process ends.
The only line of the input contains two integers n and m (1 ≤ n, m ≤ 1018). n is the initial value of variable a, and m is the initial value of variable b.
Print two integers — the values of a and b after the end of the process.
12 5
0 1
31 12
7 12
Explanations to the samples:
- a = 12, b = 5
a = 2, b = 5
a = 2, b = 1
a = 0, b = 1; - a = 31, b = 12
a = 7, b = 12.
官方题解:
The answer can be calculated very easy by Euclid algorithm (which is described in the problem statement), but all subtractions will be replaced by taking by modulo.
题意:
Euclid算法,和题意一样,我最开始是按照题目给的流程按部就班的写,a,b的范围为10^18,要开long long,但是在text3 10^18 7就TLE了。
于是后面看到大佬的代码,以及官方题解,发现-=的话,效率会很低,改成%=即可。
代码:
#include<bits/stdc++.h>
long long a, b;
int main(){
scanf("%lld %lld", &a, &b);
while(a && b){
if(a>=2*b) a%= 2*b;
else if(b>=2*a) b%=2*a;
else break;
}
printf("%lld %lld", a, b);
}
Educational Codeforces Round 39 Editorial B(Euclid算法,连续-=与%=的效率)的更多相关文章
- Educational Codeforces Round 39 (Rated for Div. 2) G
Educational Codeforces Round 39 (Rated for Div. 2) G 题意: 给一个序列\(a_i(1 <= a_i <= 10^{9}),2 < ...
- Educational Codeforces Round 39
Educational Codeforces Round 39 D. Timetable 令\(dp[i][j]\)表示前\(i\)天逃课了\(j\)节课的情况下,在学校的最少时间 转移就是枚举第\ ...
- #分组背包 Educational Codeforces Round 39 (Rated for Div. 2) D. Timetable
2018-03-11 http://codeforces.com/contest/946/problem/D D. Timetable time limit per test 2 seconds me ...
- Educational Codeforces Round 68 Editorial
题目链接:http://codeforces.com/contest/1194 A.Remove a Progre ...
- Educational Codeforces Round 39 (Rated for Div. 2) B. Weird Subtraction Process[数论/欧几里得算法]
https://zh.wikipedia.org/wiki/%E8%BC%BE%E8%BD%89%E7%9B%B8%E9%99%A4%E6%B3%95 取模也是一样的,就当多减几次. 在欧几里得最初的 ...
- Educational Codeforces Round 39 (Rated for Div. 2) 946E E. Largest Beautiful Number
题: OvO http://codeforces.com/contest/946/problem/E CF 946E 解: 记读入串为 s ,答案串为 ans,记读入串长度为 len,下标从 1 开始 ...
- Educational Codeforces Round 53 Editorial
After I read the solution to the problem, I found that my solution was simply unsightly. Solved 4 ou ...
- codeforces Educational Codeforces Round 39 (Rated for Div. 2) D
D. Timetable time limit per test 2 seconds memory limit per test 256 megabytes input standard input ...
- [Educational Codeforces Round 16]E. Generate a String
[Educational Codeforces Round 16]E. Generate a String 试题描述 zscoder wants to generate an input file f ...
随机推荐
- Netty快速入门(02)Java I/O(BIO)介绍
BIO简介 Java I/O,也叫Blocking I/O,也就是阻塞式I/O. BIO的流程比较简单,在服务端创立一个ServerSocket去监听,等待连接.客户端创建一个Socket连接过来,服 ...
- Java类成员之方法
方法含义: 1. 方法是类或对象行为特征的抽象,用来完成某个功能操作. 2.在某些语言中也称为函数或过程. 3.将功能封装为方法的目的是简化代码,可以实现代码重用. 4.在Java里的方法不能独立存在 ...
- 搭建个人OpenAPI
简介 OpenAPI Open API 即开放 API,也称开放平台. 所谓的开放 API(OpenAPI)是服务型网站常见的一种应用,网站的服务商将自己的网站服务封装成一系列 API(Applica ...
- axios全局引用
在vue项目开发中,我们使用axios进行ajax请求,很多人一开始使用axios的方式,会当成vue-resoure的使用方式来用,即在主入口文件引入import VueResource from ...
- 数学基础系列(六)----特征值分解和奇异值分解(SVD)
一.介绍 特征值和奇异值在大部分人的印象中,往往是停留在纯粹的数学计算中.而且线性代数或者矩阵论里面,也很少讲任何跟特征值与奇异值有关的应用背景. 奇异值分解是一个有着很明显的物理意义的一种方法,它可 ...
- Redis系列(二):Redis的5种数据结构及其常用命令
上一篇博客,我们讲解了什么是Redis以及在Windows和Linux环境下安装Redis的方法, 没看过的同学可以点击以下链接查看: Redis系列(一):Redis简介及环境安装. 本篇博客我们来 ...
- jenkins 配置ssh密钥登录
1.找到一台服务器执行 ssh-keygen -t rsa 会在目录/root/.ssh生成id_rsa私钥.id_rsa.pub公钥,将公钥的内容写入到同目录下的authorized_keys文件( ...
- 史上最简约的vi教程,复制和粘贴
上一篇博客,讲了"新手"如何"入门"vi,解决了"两眼一抹黑"的情况.知道在vi下如何进行基本的操作,如部署在Linux下的项目,修改配置文 ...
- python 遍历文件夹下的所有文件
基础 import os # 遍历文件夹 def walkFile(file): for root, dirs, files in os.walk(file): # root 表示当前正在访问的文件夹 ...
- [洛谷P2962] [USACO09NOV] 灯Lights
Description Bessie and the cows were playing games in the barn, but the power was reset and the ligh ...