Cod sursa(job #830302)
Utilizator | Data | 6 decembrie 2012 16:56:02 | |
---|---|---|---|
Problema | Factorial | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.63 kb |
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int zero(int x)
{
int nr = 0;
while(x >= 5)
{
nr += x / 5;
x /= 5;
}
return nr;
}
int cautare_binara(int p) //caut cel mai mare numar cu proprietatea zero(numar) < p
{
int i = 1 , pas = 1 << 20;
while(pas != 0)
{
if(zero(i + pas) < p)
i += pas;
pas /= 2;
}
return i;
}
int main()
{
int p, n;
in >> p;
n = cautare_binara(p) + 1;
if(zero(n) == p)
out << n;
else
out << -1;
return 0;
}