Cod sursa(job #2883059)

Utilizator rapidu36Victor Manz rapidu36 Data 1 aprilie 2022 09:28:06
Problema Mins Scor 50
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.34 kb
#include <fstream>
#include <vector>

using namespace std;

const int VMAX = 1e6;

int nrdp[1+VMAX], x, y;
long long rez;
vector <int> prime;

void calcul_nrdp(int n)
{
    for (int i = 2; i <= n; i++)
    {
        if (nrdp[i] == 0)
        {
            if (i * i <= n)
            {
                prime.push_back(i);///voi marca multiplii lui i
            }
            for (int multiplu = i; multiplu <= n; multiplu += i)
            {
                nrdp[multiplu]++;
            }
        }
    }
    for (auto p: prime)
    {
        int patrat = p * p;
        for (int multiplu = patrat; multiplu <= n; multiplu += patrat)
        {
            nrdp[multiplu] = -1;
        }
    }
}

int main()
{
    ifstream in("mins.in");
    ofstream out("mins.out");
    in >> x >> y;
    int n = min(x-1, y-1);
    calcul_nrdp(n);
    rez = (long long)(x- 1) * (y - 1);
    for (int i = 2; i <= n; i++)
    {
        if (nrdp[i] != -1)
        {
            long long nr_fractii_red = ((long long)(x - 1) / i) * ((long long)(y - 1) / i);
            if (nrdp[i] % 2 == 0)
            {
                rez += nr_fractii_red;
            }
            else
            {
                rez -= nr_fractii_red;
            }
        }
    }
    out << rez;
    in.close();
    out.close();
    return 0;
}