import java.util.Vector; 
import java.lang.System;


class SSum{

    
    /* return all subsets of a that add up to t, and null if there is
     * no such subset */
    public static Vector<Vector<Integer>> ssum(int[] a, int t) {

	return ssumrec(a,0, t);
    }


 
    /* return all subsets of a that add up to t, and null if there is
     * no such subset */
    public static Vector<Vector<Integer>> ssumrec(int[] a, int i, int t) {

	//basecases
	if (t==0) { 
	    //a solution exists, and its the empty set: so we just
	    //return a new vector with an empty vector as its only
	    //element NOTE: an empty vector is very different than
	    //null, which is returned when no solution exists
	    Vector<Vector<Integer>> v =  new Vector<Vector<Integer>>(); 
	    v.add(new Vector<Integer>());
	    return v; 
	}
	if (t<0) return null; 
	if (i>= a.length) return null; 


	//if we are here, its not the basecase
	Vector<Vector<Integer>> with, without; 

	with = ssumrec(a,i+1, t-a[i]); 
	without = ssumrec(a, i+1, t); 
	
	if (with != null) {
	    //we need to add a[i] to each subset in with 
	    //if with is empty, it mans this is the first element in the set 
	    for (int k=0; k< with.size(); k++) with.get(k).add(a[i]); 
	}

	//return with + without
	if (with == null && without == null) return null; 
	Vector<Vector<Integer>> v = new Vector<Vector<Integer>>(); 
	if (with != null)  v.addAll(with); 
	if (without != null)  v.addAll(without); 
	return v; 
    }



    public static Vector<Vector<Integer>> ssum2(int[] a, int t) {

	return ssumrec2(a,0,new Vector<Integer>(), t);
    }


 
    /* soFar is the partial set so far, and i is the element we are
     * currently considering.  return all subsets of a that add up to
     * t, and null if there is no such subset */
    public static Vector<Vector<Integer>> ssumrec2(int[] a, int i, 
						   Vector<Integer> soFar,  int t) {

	//basecases
	if (t==0) { 
	    //return a vector that contains soFar as its only element
	    Vector<Vector<Integer>> v =  new Vector<Vector<Integer>>(); 
	    v.add(soFar);
	    return v; 
	}
	
	if (t<0) return null; 
	if (i>= a.length) return null; 


	//if we are here, its not the basecase
	Vector<Vector<Integer>> with, without; 
	Vector<Integer> soFar2 = (Vector<Integer>)soFar.clone();
	soFar.add(a[i]);
	with = ssumrec2(a,i+1, soFar, t-a[i]); 
	without = ssumrec2(a, i+1, soFar2, t); 
	

	//return with + without
	if (with == null && without == null) return null; 
	Vector<Vector<Integer>> v = new Vector<Vector<Integer>>(); 
	if (with != null)  v.addAll(with); 
	if (without != null)  v.addAll(without); 
	return v; 
    }


    public static void main(String[] args) {

	if (args.length <2) {
	    System.out.println("Incorrect arguments");
	    System.exit(1);
	}

	//set the target
	int target = Integer.parseInt(args[0]);
	System.out.println("target=" + target);

	//set the array 
	int[] a = new int[args.length-1];
	for (int i=0; i<a.length; i++) a[i] = Integer.parseInt(args[i+1]);
	System.out.print("array is: ");
	for (int i=0; i< a.length; i++) System.out.print(a[i] + " "); 
	System.out.println("");

	
	System.out.println("sol1: the subsets are: " + ssum(a,target));
	System.out.println("sol2: the subsets are: " + ssum2(a,target));

    }

}