Cod sursa(job #1313173)
Utilizator | Alexandrescu Cristian bulbulica | Data | 10 ianuarie 2015 13:01:19 |
---|---|---|---|
Problema | Factorial | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.63 kb |
#include <fstream>
using namespace std;
int fact(int a)
{
int s=0,x=5;
while(x<=a)
{
s=s+a/x;
x = x*5;
}
return s;
}
int main()
{
int st=0,mij,dr=1000000000,p,n=-1;
ifstream f("fact.in");
ofstream g("fact.out");
f>>p;
if(p==0)
{
g<<"1";
return 0;
}
while(st<=dr)
{
mij=(st+dr)/2;
if(fact(mij)>p)
{
dr=mij-1;
}
if(fact(mij)<p)
{
st=mij+1;
}
if(fact(mij)==p)
n=mij,dr=mij-1;
}
g<<n;
return 0;
}