hdu 1261(组合数+java大数)

//组合数+java大数
import java.util.Scanner;
import java.math.BigInteger;

public class hdu1261
{
public static void main(String args[])
{
Scanner cin = new Scanner(System.in);
BigInteger f1, f2;
int []s = new int[26];
int n, sum;
n = cin.nextInt();
while (n != 0)
{
sum = 0;
for (int i=0; i<n; ++i)
{
s[i] = cin.nextInt();
sum += s[i];
}
f1 = new BigInteger("1");
for (int i=1; i<=sum; ++i)
{
f1 = f1.multiply(BigInteger.valueOf(i));
}
f2 = new BigInteger("1");
for (int i=0; i<n; ++i)
{
for (int j=1; j<=s[i]; ++j)
{
f2 = f2.multiply(BigInteger.valueOf(j));
}
}
System.out.println(""+f1.divide(f2));
n = cin.nextInt();
}
}
}