北邮OJ上的题目——1549

 

实验题三Submit: 264   Accepted:59Time Limit: 1000MS  Memory Limit: 65535K

Description
使用大整数乘法求解输入小于30的阶乘结果；

Input


Output


Sample Input

20

Sample Output

2432902008176640000

Source
import java.math.BigInteger;import java.util.*;public class the1549 {public static void main(String[] args) {Scanner cin=new Scanner(System.in);BigInteger n=new BigInteger(cin.next());BigInteger result=BigInteger.ZERO;result=factorial(n);System.out.println(result);}private static BigInteger factorial(BigInteger n) {if(n.equals(BigInteger.ONE)||n.equals(BigInteger.ZERO))return BigInteger.ONE;elsereturn n.multiply(factorial(n.subtract(BigInteger.ONE)));}}