hdu 1131 Count the Trees 卡特兰数+java

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

public class Main {

public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in=new Scanner(System.in);
int i=0,n=0;
BigInteger[] a=new BigInteger[150];
a[0]=BigInteger.ONE;
for(i=1;i<=105;i++)
a[i]=a[i-1].multiply(BigInteger.valueOf(4*i-2)).divide(BigInteger.valueOf(i+1));
while(in.hasNextInt())
{
n=in.nextInt();
if(n==0) break;
BigInteger ans=BigInteger.ONE;
for(i=1;i<=n;i++)
ans=ans.multiply(BigInteger.valueOf(i));
ans=ans.multiply(a
);
System.out.println(ans);
}
in.close();
}

}