java - 如何编写超阶乘程序？

Question

Write a program to calculate and print the super factorial of a number using a for loop. The factorial of a number is the product of all integers up to and including that number, so the factorial of 4 (written as 4!) is 4*3*2*1= 24.

The super factorial is the product of all factorials up to and including that factorial.

4!!=4!*3!*2!*1!

我使用以下代码找到了“阶乘”:

import java.util.Scanner;
public class superfactorial {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner (System.in);

        // number whose factorial to be found
        int number;
        // prompting input
        System.out.print("Enter number: ");
            number = input.nextInt();

        int factorial = factorial(number);

        System.out.printf("the factorial of %d is %d", number , factorial);
    }

    // method that calculates the factorial
    public static int factorial (int n){
        int output = 1; 
        for (int i=1; i <= n; i++) {
            output = output * i;                
        }
            return output;
    }
}

Answer 1

考虑4! = 4x​​3x2x1，可以看到分解中有4个数字。一般来说n的分解会有n个数! (n(n-1)(n-2)....(n-(n-1))。因此，要获得超阶乘，您需要做的就是获取分解中每个分量的阶乘。

伪代码看起来像这样

sp = 0 
for i = n to 1:
  sp = sp * factorial(i)
end for
return sp