【Poi2007】【Bzoj1101】Zap

 1 #include<cstdio>
 2 #include<algorithm>
 3 #define ll long long
 4 using namespace std;
 5 const int maxn=50010;
 6 const int N=50000;
 7 int T,a,b,d,p;
 8 int prime[maxn],mu[maxn];
 9 bool is_prime[maxn]; 
10 void get_mu(){
11     for (int i=0; i<=N; i++) is_prime[i]=true;
12     is_prime[0]=is_prime[1]=false;
13     mu[1]=1;
14     for (int i=2; i<=N; i++){
15         if (is_prime[i]){
16             prime[++p]=i;
17             mu[i]=-1;
18         }
19         for (int j=1; j<=p; j++){
20             if (i*prime[j]>N) break;
21             is_prime[i*prime[j]]=false;
22             if (i % prime[j]==0) {
23                 mu[i*prime[j]]=0;
24                 break;
25             }
26             else mu[i*prime[j]]=-mu[i];
27         }
28     }
29     for (int i=2; i<=N; i++) mu[i]+=mu[i-1];
30 }
31 int solve(int a,int b){
32     int res=0;
33     if (a>b) swap(a,b);
34     int pos=0;
35     for (int i=1; i<=a; i=pos+1){
36         pos=min(a/(a/i),b/(b/i));
37         res+=(mu[pos]-mu[i-1])*(a/i)*(b/i);
38     }
39     return res;
40 }
41 int main(){
42     get_mu();
43     scanf("%d",&T);
44     while (T--){
45         scanf("%d%d%d",&a,&b,&d); 
46         printf("%d\n",solve(a/d,b/d));
47     }
48     return 0;
49 }