Cod sursa(job #796569)

Utilizator mipsPavel Mircea mips Data 11 octombrie 2012 20:38:20
Problema Frac Scor 40
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.06 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <cstdio>
#include <set>
using namespace std;
ifstream inp("frac.in");
ofstream outp("frac.out");
int main()
{
    unsigned long long n,nn,nsr2,p;
    inp >> n >> p;
    nn=n;
    nsr2 = sqrt(n)+1;
    unsigned long long di=2;
    vector<unsigned long long> divisors;

    while (nn!=1)
    {
        if (nn%di==0)
            divisors.push_back(di);
        while (nn%di==0)
        nn/=di;
        di++;
        if (di>nsr2)
        {
            divisors.push_back(n);
        }
    }

    //for (int j = 0;j<divisors.size();j++)
    //cout << divisors[j]<<" ";

    vector<unsigned long long> combFact;
    vector<unsigned long long> nr1;
    for (unsigned long long i=0;i<1<<divisors.size();i++)
    {
        //cout << "i:" << i <<endl;
        unsigned long long pr=1;
        int nr0=0;
        for (int j = 0;j<divisors.size();j++)
        {
          //  cout << "j:" << i <<endl;
            if (i &(1<<j))
            {
                pr*=divisors[j];
                nr0++;
            }

        }
        if (nr0)
        {
            combFact.push_back(pr);
            nr1.push_back(nr0);
        }
        //cout << pr<<" "<<nr0<<endl;
    }
    unsigned long long res=0;
    unsigned long long ll = 0;
    unsigned long long rr=0x2000000000000001;

    unsigned long long final=0;
    while (ll<rr)
    {
        unsigned long long mm = (ll+rr)/2;
        res=0;
        for (int i=0;i<combFact.size();i++)
        if (nr1[i]%2==1)
        {
            res+=mm/combFact[i];
            //cout << "add" <<mm/combFact[i]<<endl;
        }
        else
        {
            res-=mm/combFact[i];
            //cout << "sub" <<mm/combFact[i]<<endl;
        }

        res = mm - res;
        //cout << "la " << mm << ":"<< res<<endl;
        if (res == p)
        {
            final=mm;
            rr = mm-1;
        }
        else
        if (res < p)
        {
            ll = mm + 1;
        }
        else
        {
            rr = mm-1;
        }
    }



    outp << final;
}

/*
10
+5
+3
-1
7
*/