题目链接 link Solution 这是一道结论题,有两个做法,分别用了欧拉函数或一点点莫比乌斯反演 (这里只放欧拉函数的做法) 设\(d=gcd(m,a)\) \[gcd(\frac{a}{d},\frac{m}{d})=gcd(\frac{x+a}{d},\frac{m}{d})=1\] 从互质的关系入手进行考虑 所以答案就是\(\varphi(\frac{m}{d})\) 这个东西是可以在时限内求解的 CODE #include<bits/stdc++.h> using namespa…

Cyclic GCDs 题目链接 题面描述 有\(n\)个点,每个点有权值. 现有排列\(P\),\(p_i\)表示\(i\)个点向\(p_i\)连了一条边. 显然会形成若干个简单环.每个简单环的权值定义为环上最小的权值,一张图的权值定义为所有环的权值的乘积. 所有形成了\(k\)个简单环的图的权值和记为\(b_k\) 现在要求\(b_1,b_2...b_n\)的最大公因数. 输出对大质数取模. \(n\le10^5\) 解题思路 首先可以发现,顺序无关紧要,为了方便处理,我们把权值从小到大排序…

题目链接:Same GCDs 题意:给你两个数$a$,$m(1 \leq a < m \leq 10^{10})$,求有多少个$x$满足:$0 \leq x < m$且$gcd(a,m)=gcd(a+x,m)$ 思路:设$gcd(a,m)=d$,那么问题转换为求多少个$k \in [a,a+m)$满足$gcd(k,m)=d$ 两边同时除$d$,转换为求有多少$k \in [\frac{a}{d},\frac{a+m}{d})$满足$gcd(k,\frac{m}{d})=1$ 设$x=\frac…

https://codeforces.com/contest/1295/problem/D 设gcd(a,m)= n,那么找gcd(a +x ,m)= n个数,其实就等于找gcd((a+x)/n,m/n) = 1的个数,等价于求m/n的欧拉函数 #include<bits/stdc++.h> typedef long long ll; using namespace std; ll euler_phi(ll n) { ll m = ll(sqrt(n + 0.5)); ll ans = n;…

一.数据库 SQL: SQL是Structured Query Language(结构化查询语言)的缩写.SQL是专为数据库而建立的操作命令集, 是一种功能齐全的数据库语言. 二.数据库管理系统 数据库特征: 1.以一定方式存储在一起 2.能为多个用户共享 3.具有尽可能少的冗余代码 4.与程序彼此独立的数据集合 三.表 表是数据库中一个非常重要的对象, 是其他对象的基础根据信息的分类情况, 一个数据库中可能包含若干个数据表…

题目链接 http://acm.split.hdu.edu.cn/showproblem.php?pid=5869 Problem Description This is a simple problem. The teacher gives Bob a list of problems about GCD (Greatest Common Divisor). After studying some of them, Bob thinks that GCD is so interesting.…

Different GCD Subarray Query Problem Description   This is a simple problem. The teacher gives Bob a list of problems about GCD (Greatest Common Divisor). After studying some of them, Bob thinks that GCD is so interesting. One day, he comes up with a…

Different GCD Subarray Query Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 681    Accepted Submission(s): 240 Problem Description This is a simple problem. The teacher gives Bob a list of prob…

Hearthstone 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5816 Description Hearthstone is an online collectible card game from Blizzard Entertainment. Strategies and luck are the most important factors in this game. When you suffer a desperate situ…

Balls and Boxes 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5810 Description Mr. Chopsticks is interested in random phenomena, and he conducts an experiment to study randomness. In the experiment, he throws n balls into m boxes in such a manner t…