集合求解Java

import java.util.Scanner;

public class Main{
    public static void main(String[] args){
       Scanner sc=new Scanner(System.in);
       long sum=0;
       long num=0;
       while(sc.hasNext()) {
    	   long l=sc.nextLong();
    	   sum+=l;
    	   num++;
       }
       while(num>1) {
    	   sum*=2;
    	   num--;
       }
        System.out.println(sum);
    }
    
}

集合中每个数都出现2^（n-1）次