Cod sursa(job #2018411)

Utilizator AlexandruOlteanuOlteanu Alexandru AlexandruOlteanu Data 4 septembrie 2017 20:28:10
Problema Fractii Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.35 kb
Raporteaza aceasta sursa 
#include<bits/stdc++.h>
using namespace std;
ifstream in("fractii.in");
ofstream out("fractii.out");
int v[1000005];
int main()
{long long n,i,j,s=0;
in>>n;
for(i=1;i<=n;++i)
    v[i]=i-1;
for(i=2;i<=n;++i)
    for(j=2*i;j<=n;j+=i)
      v[j]-=v[i];
v[1]=1;
for(i=1;i<=n;++i)
    s+=v[i];
out<<2*s-1;
in.close();
out.close();
return 0;

}