大乐的博客

题目链接：https://www.lydsy.com/JudgeOnline/problem.php?id=2154 在这位大神的blog里才看懂，有时间再自己写一下https://www.cnblogs.com/cjyyb/p/8253033.html#include<bits/stdc++.h>#include<math.h>#define MOD...

题目链接：https://www.lydsy.com/JudgeOnline/problem.php?id=2301求a<=x<=b,c<=y<=d中gcd（x，y）=k的数对对数先莫比乌斯反演求出1~a和1~b中的gcd=k的对数，在容斥一下。ans=pin(b,d)+pin(a,c)-pin(b,c)-pin(a,d);#include<bits...

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5663#include<bits/stdc++.h>#include<math.h>#define MOD 20101009#define For(i,m,n) for(int i=m;i<=n;i++)#define LL long long#def...

题目链接；http://acm.hdu.edu.cn/showproblem.php?pid=6053最后减得时候可能会小于0所以要加模 #include<bits/stdc++.h>#include<math.h>#define MOD 1000000007#define For(i,m,n) for(int i=m;i<=n;i++)#de...