Cod sursa(job #2478440)

Utilizator SergiuS3003Sergiu Stancu Nicolae SergiuS3003 Data 22 octombrie 2019 08:20:52
Problema Frac Scor 60
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.28 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("frac.in");
ofstream g("frac.out");
long long N, P, R, divp[20];
int nrd, nt;
void divizorip(long long x)
{
    nrd = 0;
    if(x % 2 == 0)
    {
        divp[++nrd] = 2;
        do
        {
            x /= 2;
        }
        while(x % 2 == 0);
    }
    for(long long i = 3; i * i <= x; i += 2)
        if(x % i == 0)
        {
            divp[++nrd] = i;
            do
            {
                x /= i;
            }
            while(x % i == 0);
        }
    if(x > 1)
        divp[++nrd] = x;
}
long long calcul(long long x)
{
    long long rez = x;
    for(int i = 1; i < nt; i++)
    {
        long long prod = 1;
        for(int j = 0, p2; (p2 = 1 << j) <= i; j++)
            if(i & p2)
                prod *= -divp[j + 1];
        rez += x / prod;
    }
    return rez;
}
int main()
{
    f >> N >> P;
    divizorip(N);
    nt = 1 << nrd;
    int p = 1;
    long long u = 1LL << 61; ///Se garanteaza ca rezultatul nu depasete 1<<61
    while(p <= u)
    {
        long long m = (p + u) / 2;
        if(calcul(m) < P)
            p = m + 1;
        else
        {
            R = m;
            u = m - 1;
        }
    }
    g << R;
    return 0;
}