计算集合划分的非空子集数量

package chapter2;
import java.io.*;

public class SetPartition {

public static void main(String[] args) throws IOException {
int num;
int count=0;

FileReader fr=new FileReader("C:/算法/2/SET PARTITION/TEST/BELL0.IN");
BufferedReader br=new BufferedReader(fr);
FileWriter fw=new FileWriter("C:/算法/2/SET PARTITION/ANSWER/BELL1.OUT");
BufferedWriter bw =new BufferedWriter(fw);

long startTime=System.nanoTime();
num=Integer.parseInt(br.readLine());
        count=nonEmpSub(num);

fr.close();
br.close();
long endTime=System.nanoTime();
System.out.println("实验二 递归与分治");
System.out.println("题目：MAJORITY");
System.out.println("姓名：张臻跃  学号：1107122201");
System.out.println("运行时间："+(endTime-startTime)+"ns");
System.out.println("输入测试数据：MODE2.IN");
System.out.println("输出："+num+"\n"+count);
bw.write(String.valueOf(num));
bw.newLine();
bw.write(String.valueOf(count));