Cod sursa(job #1333438)

Utilizator Darius15Darius Pop Darius15 Data 3 februarie 2015 10:04:27
Problema GFact Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.16 kb
#include <fstream>
#include <bitset>
#include <cmath>
using namespace std;
ifstream f("gfact.in");
ofstream g("gfact.out");
int n,c,i,j,l,v[25];
long long st,dr,vd,p,exp1[25],exp3[25],m,best;
bitset <100001> viz;
bool ok;
int main()
{
    f>>n>>m;
    c=sqrt(n);
    if (n%2==0){
            v[1]=2,l=1;
    while(n%v[1]==0)
        n=n/v[1],exp1[1]++;
    }
    for (i=3;i<=c;i+=2)
        if (viz[i]==false)
    {
       j=i*i;
       if (j/i==i)
        for (j=i*i;j<=c;j+=i)
         viz[j]=true;
         if (n%i==0){
            v[++l]=i;
       while(n%i==0)
        n=n/i,exp1[l]++;
         }
    }
    if (n>1)
    {
        v[++l]=n,exp1[l]++;
    }
    for (i=1;i<=l;i++)
       exp1[i]=exp1[i]*m;
    st=1,dr=1ll<<60-1;
    best=-1;
    while(st<=dr)
    {
        m=(st+dr)/2;
        for (i=1;i<=l;i++)
            exp3[i]=0;
            ok=true;
        for (i=1;i<=l;i++)
        {
            p=1;
            while(p<=m/v[i])
            p=p*v[i],exp3[i]+=m/p;

            if (exp3[i]<exp1[i]) ok=false;
        }
        if (ok==true) best=m,dr=m-1;
        else st=m+1;
    }
    g<<best<<' ';
    return 0;
}