Cod sursa(job #2668124)

Utilizator metallidethantralayerIon Cojocaru metallidethantralayer Data 4 noiembrie 2020 15:22:00
Problema Fractii Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.44 kb
#include <bits/stdc++.h>

using namespace std;
int T,n;
vector <int> Ciur(1000005);
int main()
{
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    f>>T;
    for(int i=2; i<=1000000; i++)
        Ciur[i]=i-1;
    for(int i=1; i<=1000000; i++)
        for(int j=2*i; j<=1000000; j+=i)
            Ciur[j]-=Ciur[i];
    int64_t S=0;
    for(int i=2; i<=T; i++)
        S+=Ciur[i];
    g<<(S<<1)+1;
    return 0;
}