Cod sursa(job #1268235)
Utilizator | Radu Cosma radu_cosma | Data | 20 noiembrie 2014 19:10:22 |
---|---|---|---|
Problema | Factorial | Scor | 80 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.59 kb |
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int verif(int n)
{
int s=0,p=5;
while(p<=n)
{
s+=n/p;
p*=5;
}
return s;
}
int main()
{
int n,st=1,dr=200000000,p,x,nr,a,m=1;
in>>p;
if(p==0) out<<1<<"/n";
else
{
m=1;
while(st<=dr&&m)
{
x=(st+dr)/2;
a=verif(x);
if(a==p) {nr=x-x%5;
m=0;}
else
if(a<p) st=x+1;
else
dr=x-1;
}
if(m==0) out<<nr<<"/n";
else out<<-1<<"/n";
}
return 0;
}