Cod sursa(job #521643)

Utilizator titeltitel popescu titel Data 12 ianuarie 2011 23:56:02
Problema Principiul includerii si excluderii Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 0.87 kb
#include<fstream.h>
ifstream f("pinex.in"); ofstream g("pinex.out");
char ciur[1000005]; //ciur[i] == 0 daca i este prim
long long a,b,sum,s,pr,p[100001],d[30];
int T,i,j,n,nr=0,m,k,x[30];
void prelsol()
{long long pr=1;
 for(int i=1; i<=n; i++) pr=pr*d[x[i]];
 s+=a/pr;
}
void back()
{s=0; k=1; x[k]=0;
 do {while(x[k]<m-n+k)
		{x[k]++;
		 if(k==n) prelsol(); 
		  else {k++; x[k]=x[k-1];};
		}
	 k--;	
	}
 while(k); 
 if(n%2) sum+=s; else sum-=s;
} 
int main()
{for(i=2; i<=500000; i++)
  if(!ciur[i])
   {p[++nr]=i;
	for(j=i+i; j<=1000000; j+=i) ciur[j]=1;
   };
 f>>T;
 while(T)  
   {f>>a>>b;
	m=0; i=1;
    while(b>1 && p[i]*p[i]<=b)
	  {if(b%p[i]==0)
		  {d[++m]=p[i];
		   while(b%p[i]==0) b/=p[i];
		  };
		i++;
	  }
	if(b>1) d[++m]=b;
	sum=0; 
	for(n=1; n<=m; n++)
		back();
	g<<a-sum<<'\n';  
	T--;
   }
 g.close(); return 0;
}