bzoj2880

打公式好麻烦　QAQ　　

为了节省时间去复习，原谅我引用一下别人的博客。。。http://blog.csdn.net/acdreamers/article/details/8542292

 #include<iostream>
 #include<cstdio>
 #include<cstdlib>
 #include<string>
 #include<cstring>
 #define re(i,l,r) for(int i=(l);i<=(r);i++)
 #define rre(i,r,l) for(int i=(r);i>=(l);i--)
 using namespace std;
 typedef long long LL;
 int prime[],prime_tot,mu[],g[],sum[];
 bool bo[];
 LL solve(int n,int m)
 {
     LL ret=;
     if(n>m)swap(n,m);
     int i=,xia;
     while(i<=n)
     {
         xia=min(n/(n/i),m/(m/i));
         ret+=1LL*(n/i)*(m/i)*(sum[xia]-sum[i-]);
         i=xia+;
     }
     return ret;
 }
 int main()
 {
     mu[]=;
     re(i,,)
     {
         if(!bo[i])prime[++prime_tot]=i,mu[i]=-,g[i]=;
         for(int j=;j<=prime_tot&&i*prime[j]<=;j++)
         {
             bo[i*prime[j]]=;
             if(i%prime[j]==){mu[i*prime[j]]=,g[i*prime[j]]=mu[i];break;}
             else mu[i*prime[j]]=-mu[i],g[i*prime[j]]=mu[i]-g[i];
         }
     }
     re(i,,)sum[i]=sum[i-]+g[i];
     int t;
     scanf("%d",&t);
     while(t--)
     {
         int n,m;scanf("%d%d",&n,&m);
         printf("%lld\n",solve(n,m));
     }
     return ;
 }