记录编号	598190	评测结果	AAAAAAAAAA
题目名称	[清华集训 2012] 模积和	最终得分	100
用户昵称	郑霁桓	是否通过	通过
代码语言	C++	运行时间	0.130 s
提交时间	2025-01-20 22:37:26	内存使用	3.34 MiB

#include<bits/stdc++.h>
using namespace std;
long long a,b,s,s1,s2,as,M=19940417,a2=9970209,a6=3323403;
long long f(long long x){
	return x*(x+1)%M*(2*x+1)%M*a6%M;
}
int main(){
	freopen("modmuladd.in","r",stdin);
	freopen("modmuladd.out","w",stdout);
	ios::sync_with_stdio(false);
	cin>>a>>b;
	if(a>b) swap(a,b);
	for(long long i=1,j;i<=a;i=j+1){
		j=a/(a/i);
		s1+=(i+j)*(j-i+1)%M*a2%M*(a/i)%M;
		s1%=M;
	}
	for(long long i=1,j;i<=b;i=j+1){
		j=b/(b/i);
		s2+=(i+j)*(j-i+1)%M*a2%M*(b/i)%M;
		s2%=M;
	}
	as=(a*a%M-s1+M)%M*(b*b%M-s2+M)%M;
	s1=s2=0;
	for(long long i=1,j;i<=a;i=j+1){
		j=min(a/(a/i),b/(b/i));
		s1+=(a*b%M*(j-i+1)%M+(a/i)%M*(b/i)%M*(f(j)-f(i-1)))%M;
		s2+=(i+j)*(j-i+1)%M*a2%M*((a/i)%M*b%M+(b/i)%M*a%M)%M;
		s1%=M,s2%=M;
	}
	as=(as-s1+s2+M)%M;
	cout<<as%M;
    return 0;
}