A - Hex Factorial

传送门：http://acm.hust.edu.cn/vjudge/contest/view.action?cid=80660#problem/A

题意：求N！的十六进制中，有多少个零，不含前导零

import java.math.BigInteger;
import java.util.Scanner;


public class Main {


public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc = new Scanner(System.in);
while(sc.hasNext())
{
int n = sc.nextInt();
if(n==0)
{
System.out.println("0");
continue;
}
else if(n<0)
{
continue;
}
else
{
BigInteger res = BigInteger.valueOf(1);
BigInteger zero = BigInteger.valueOf(0);
BigInteger sixteen = BigInteger.valueOf(16);
for(int i=1;i<=n;i++)
{
res = res.multiply(BigInteger.valueOf(i));
}
int ans=0;
while(true)
{
if(res.equals(zero)==true)
break;
BigInteger temp = res.mod(sixteen);
if(temp.equals(zero)==true)
ans++;
res = res.divide(sixteen);
}
System.out.println(ans);
}
}
}
}