Cod sursa(job #2781556)

Utilizator lolismekAlex Jerpelea lolismek Data 9 octombrie 2021 19:59:01
Problema Sum Scor 55
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.77 kb
#include <iostream>
#include <fstream>
using namespace std;
const int MAX = 100005;
int phi[MAX];

int main()
{
    long long n, x, i, j;
    /// alcatuim indicatorul lui euler
    for(i = 1; i <= MAX; i++)
    {
        phi[i] = i;
    }
    for(i = 2; i <= MAX; i++)
    {
        if(phi[i] == i)
        {
            for(j = i; j <= MAX; j+= i)
            {
                phi[j] = phi[j] / i * (i - 1);
            }
        }
    }


    ifstream fin;
    fin.open("sum.in");
    ofstream fout;
    fout.open("sum.out");
    fin >> n;
    for(i = 0; i < n; i++)
    {
        fin >> x;
        /// formula dedusa din demonstratie matematica:
        fout << 2 * phi[x] * x << endl;
    }
    fin.close();
    fout.close();
    return 0;
}