Cod sursa(job #811442)
Utilizator | Babalau Alexandru alex_Harry | Data | 12 noiembrie 2012 12:39:11 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.63 kb |
#include<fstream>
using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
void read_number(int& n)
{
f>>n;
}
int is_prime(int x)
{
int i;
if(x==2)
return(1);
for(i=2;i<x;i++)
{
if(x%i==0)
return(0);
if(x/i<i)
return(1);
}
return(0);
}
int Gauss(int n)
{
return(n*(n+1)/2);
}
void ciur(int n)
{
int i,cont=0;
for(i=2;i<=n;i++)
{
if(is_prime(i)==1)
cont+=Gauss((n-i)/i)*2;
}
cont+=n-1;
g<<n*n-cont<<"\n";
}
int main()
{
int n;
read_number(n);
ciur(n);
}