HDU 1023 Traning Problem （2） 大数卡特兰数

import java.io.*;  
import java.util.*;  
import java.math.BigInteger;  
  
  
public class Main  
{  
    public static void main(String args[])  
    {         
        BigInteger[] a = new BigInteger[101];  
        a[0] = BigInteger.ZERO;  
        a[1] = BigInteger.valueOf(1);  
        for(int i = 2; i <= 100; ++i)  
            a[i] = a[i - 1].multiply(BigInteger.valueOf(4 * i - 2)).divide(BigInteger.valueOf(i+1));  
            Scanner in = new Scanner(System.in);  
            int n;  
            while(in.hasNext())  
            {  
                n = in.nextInt();  
                System.out.println(a[n]);  
            }  
    }  
}