Cod sursa(job #2580740)
Utilizator | Data | 14 martie 2020 01:38:32 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.36 kb |
#include <fstream>
using namespace std;
ifstream fin("fractii.in");
ofstream fout("fractii.out");
int prime[1000001],n,i,j;
long long sol;
int main(){
fin>>n;
for(i=1;i<=n;i++)
prime[i]=i-1;
for(i=1;i<=n;i++){
for(j=2*i;j<=n;j+=i)
prime[j]-=prime[i];
sol+=prime[i];
}
fout<<1+2*sol;
}