Cod sursa(job #3219353)
Utilizator | Zgorcea Mihai-Alexandru Warrior.exe | Data | 31 martie 2024 09:08:56 |
---|---|---|---|
Problema | Fractii | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.52 kb |
#include <iostream>
#include <fstream>
using namespace std;
int euler[1000000];
int main(){
ifstream cin("fractii.out");
ofstream cout("fractii.out");
int nr;
cin>>nr;
for(int i=1;i<=nr;i++){
euler[i]=i;
}
for(int i=2;i<=nr;i++){
if(euler[i]==i){
for(int j=i;j<=nr;j+=i){
euler[j]=euler[j]/i*(i-1);
}
}
}
long long s=0;
for(int i=1;i<=nr;i++){
s+=euler[i];
}
cout<<s*2-1;
return 0;
}