Cod sursa(job #2204628)

Utilizator triscacezarTrisca Vicol Cezar triscacezar Data 16 mai 2018 18:48:07
Problema Fractii Scor 90
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.32 kb
Raporteaza aceasta sursa 
#include <bits/stdc++.h>

using namespace std;
ifstream f("fractii.in");
ofstream g("fractii.out");
long long i,j,n,a[1000010];
int main()
{
    f>>n;
    for(i=1;i<=n;i++)
    {
        a[i]+=i;
        for(j=i*2;j<=n;j+=i)
            a[j]-=a[i];
        a[i]+=a[i-1];
    }
    g<<2*a[n]-1;

    return 0;
}