Cod sursa(job #1577210)
| Utilizator | Data | 23 ianuarie 2016 12:24:48 | |
|---|---|---|---|
| Problema | Fractii | Scor | 0 |
| Compilator | cpp | Status | done |
| Runda | Arhiva de probleme | Marime | 0.25 kb |
#include <fstream>
using namespace std;unsigned long long s[1000001],n,i,j,rifstream fin("fractii.in");ofstream fout("fractii.out");int main(){fin>>n;for(i=2;i<=n;i++){s[i]=i-1;}for(i=2;i<=n;i++){r+=s[i];for(j=i+i;j<=n;j=j+i){s[j]-=s[i];}}r*=2;fout<<r+1;}
