Cod sursa(job #1587871)
Utilizator | Data | 2 februarie 2016 17:18:50 | |
---|---|---|---|
Problema | Factorial | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.54 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int nz(int x)
{
int ans=0,p5=5;
while(x>=p5)
{
ans=ans+x/p5;
p5=p5*5;
}
return ans;
}
int main()
{
int p,st,dr;
fin>>p;
st=1;dr=500000000;
while(st<=dr)
{
int mij=(st+dr)/2;
if(nz(mij)<p)
st=mij+1;
else
dr=mij-1;
}
if(nz(st)==p)
fout<<st;
else
fout<<-1;
return 0;
}