public class TwoArrAssemble {
    static void combination(int[][] array, int alength, int blength, int sub) {
        if (sub >= array[0].length) {
            int a = 0, b = 0;
            for (int j = 0; j < array[0].length; ++j) {
                if (j < alength)
                    a += array[1][j];
                else
                    b += array[1][j];
            }
            if (a != 0 && b != 0) {
                for (int j = 0; j < array[0].length; ++j)
                    if (array[1][j] == 1)
                        System.out.print(array[0][j] + "  ");
                System.out.println();
            }
            return;
        }
        array[1][sub++] = 1;
        combination(array, alength, blength, sub);
        array[1][sub - 1] = 0;
        combination(array, alength, blength, sub);
    }

    public static void main(String[] args) {
        int[] a = { 1, 3};
        int[] b = { -2, -4};
        int[][] array = new int[2][a.length + b.length];
        for (int i = 0; i < array[0].length; ++i) {
            if (i < a.length)
                array[0][i] = a[i];
            else
                array[0][i] = b[i - a.length];
            array[1][i] = 1;
        }
        combination(array, a.length, b.length, 0);
    }
}


1  3  -2  -4  
1  3  -2  
1  3  -4  
1  -2  -4  
1  -2  
1  -4  
3  -2  -4  
3  -2  
3  -4

------解决方案--------------------
以从一个数组里所有组合的代码修改一下

import java.util.Vector;

//在N个数组里分别在每个数组里选出至少一个元素组成新的数组
public class SelectNumbers
{
	//在source数组里从startIndex之后（含startIndex）开始选出cout个不同的数字。结果添加进vresult向量
	public void selectInArray(int [] source, Vector<String> vresult, String result, int startIndex, int cout)
	{
		if (cout == 1)
		{
			String s1 = result + "," + source[startIndex];
			vresult.add(s1.substring(1));
			return;
		}
		for (int i=startIndex+1; i<source.length; i++)
			selectInArray(source, vresult, result + "," + source[startIndex], i, cout-1);
	}
	
	public void display(Vector<String> vs1, Vector<String> vs2)
	{
		for (int i=0; i<vs1.size(); i++)
			for (int j=0; j<vs2.size(); j++)
				System.out.println("(" + vs1.get(i) + ")(" + vs2.get(j) + ")");	
	}
	
	public static void main(String [] args)
	{
		SelectNumbers demo = new SelectNumbers();
		int [][] arrSource = {{1, 3}, {-2, -4}};//arrSource一维长度就是代表数组个数N
		Vector<String>[] arrvs = new Vector[arrSource.length];
		for (int i=0 ; i<arrSource.length; i++)
		{
			arrvs[i] = new Vector<String>();
			for (int startIndex=0; startIndex< arrSource[i].length; startIndex++)
				for (int cout=1; cout<=arrSource[i].length-startIndex; cout++)
				{
					String result = "";
					demo.selectInArray(arrSource[i], arrvs[i], result, startIndex, cout);
				}
		}
		demo.display(arrvs[0], arrvs[1]);
	}
}