Bzoj2301 [HAOI2011]Problem b 莫比乌斯反演

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring> 
 4 #include <algorithm>
 5 using namespace std;
 6 const int MAXN=50000+1;
 7 bool check[MAXN];
 8 int prime[MAXN],miu[MAXN],sum[MAXN];
 9 void Mobius()
10 {
11     memset(check,false,sizeof(check));
12     miu[1]=1;
13     int tot=0;
14     for(int i=2;i<=MAXN;i++)
15     {
16         if(!check[i])
17         {
18             prime[tot++]=i;
19             miu[i]=-1;
20         }
21         for(int j=0;j<tot;j++)
22         {
23             if(i*prime[j]>MAXN) break;
24             check[i*prime[j]]=true;
25             if(i%prime[j]==0)
26             {
27                 miu[i*prime[j]]=0;
28                 break;
29             }
30             else miu[i*prime[j]]=-miu[i];
31         }
32         
33     }
34 }
35 long long calc(int n,int m)
36 {
37     long long ret=0;
38     if(n>m) swap(n,m);
39     int next=0;
40     for(int i=1;i<=n;i=next+1)
41     {
42         next=min(n/(n/i),m/(m/i));
43         ret+=(long long)(sum[next]-sum[i-1])*(n/i)*(m/i);  
44     }
45     return ret;
46 }
47 int main()
48 {
49     Mobius();
50     for(int i=1;i<=MAXN;i++)
51     sum[i]=sum[i-1]+miu[i];
52     int a,b,c,d,k,t;
53     scanf("%d",&t);
54     while(t--)
55     {
56         scanf("%d%d%d%d%d",&a,&b,&c,&d,&k);
57         printf("%lld\n",calc(b/k,d/k)-calc((a-1)/k,d/k)-calc((c-1)/k,b/k)+calc((a-1)/k,(c-1)/k));
58     }
59 }