HDU 4135 Co-prime

#include <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <stack>
#include <map>
#include <queue>
#include <utility>
using namespace std;

#define rep(i,j,k) for (int i=j;i<=k;i++)
#define Rrep(i,j,k) for (int i=j;i>=k;i--)

#define Clean(x,y) memset(x,y,sizeof(x))
#define LL long long
#define ULL unsigned long long
#define inf 0x7fffffff
#define mod %100000007

int T;
LL A,B;
int n,m;
int p[50];

void init(int x)
{
m = 0;
for(int i = 2; i * i <= x; i++)
if ( x%i == 0 )
{
p[++m] = i;
while( x % i == 0 ) x/=i;
}
if ( x>1 ) p[++m] = x;
}

LL cal(LL x)
{
LL ans = 0;
int uplim = 1<<m;
rep(i,1,uplim-1)
{
int num = 0;
int cnt = 1;
rep(j,0,m-1)
if ( i & (1<<j) )
{
num++;
cnt*=p[j+1];
}
if( num & 1 ) ans+=x/cnt;
else ans-=x/cnt;
}
return x-ans;
}

int main()
{
scanf("%d",&T);
rep(kase,1,T)
{
scanf("%I64d %I64d %d",&A,&B,&n);
init(n);
printf("Case #%d: %I64d\n",kase,cal(B)-cal(A-1));
}
}