Divide.zip

package algorithm.lesson2; import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class Divide { public static void main(String[] args) throws FileNotFoundException { System.out.println("递归与分治\n" +"题目：集合划分问题\n"); Scanner scanner; for(int j=0;j<6;j++){ scanner=new Scanner(new File("BELL"+j+".IN")); int in=scanner.nextInt(); int sum=0; long startTime=System.nanoTime(); for(int i=1;i<=in;i++) { sum+=f(in,i); } System.out.println("-----------------------------------------------\n"+ "输入："+in+"\n" + "输出："+sum+"\n"+ "运行时间："+(System.nanoTime()-startTime)+" ns"); } } static int f(int n,int m) { if(m==1||n==m) return 1; else return f(n-1,m-1)+f(n-1,m)*m; } }