public static void main(String[] args) {
        // TODO Auto-generated method stub
        ThreeSum t = new ThreeSum();
        int[] arr = {-2, 0, 0, 2, 2};
        for (List<Integer> l : t.threeSum(arr)) {
            for (int i : l)
                System.out.print(i + "  ");
            System.out.println();
        }
    }