Cod sursa(job #1393952)
Utilizator | Data | 19 martie 2015 21:25:39 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.37 kb |
#include <iostream>
#include <fstream>
using namespace std;
int n,i,j,v[1000005];
long long s=1;
int main(void)
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f>>n;
for (i=2;i<=n;i++)
v[i]=i-1;
for (i=2;i<=n;i++)
{
s=s+2*v[i];
for(j=2*i;j<=n;j+=i)
v[j]=v[j]-v[i];
}
g<<s;
return 0;
}