Cod sursa(job #1585924)

Utilizator rares98_priPopa Rares rares98_pri Data 31 ianuarie 2016 16:33:54
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.3 kb
Raporteaza aceasta sursa 
#include <iostream>
#include <fstream>
using namespace std;
ifstream in ("fractii.in");
ofstream out ("fractii.out");
int i,j,n;
long long nr=1;

int main(){
in>>n;
int a[n];
for(i=1;i<=n;i++)a[i]=i-1;
for(i=2;i<=n;i++){
    for(j=i+i;j<=n;j+=i)
            a[j]-=a[i];
nr+=2*a[i];}
out<<nr;}