java小鸟求助大神

[AT152S]

题目：列出所有a数组中两个元素之和为b的下标
我写的如下，但是不对

public static void main(String[] args) {
        Test02 t = new Test02();
        int a[] = {1, 3, 5, 7, 6, 8, 7, 9, 1, 3, 2, 4};
        int b = 8;
        List list = new ArrayList();
            list = t.ret(a, b);
            for (int i = 0; i < list.size(); i++) {
                System.out.println(list.get(i));
        }
    }
    public List<int[]> ret(int[] a, int b) {
        List list = new ArrayList();
        for (int i = 0; i < a.length; i++) {
            for (int j = 1 + i; j < a.length; j++) {
                if (a[i] + a[j] == b) {
                    list.add(a[i], a[j]);
                }
            }
        }
        return list;
    };

[qybao]

public static void main(String[] args) {
        Test02 t = new Test02();
        int a[] = {1, 3, 5, 7, 6, 8, 7, 9, 1, 3, 2, 4};
        int b = 8;
        List list = new ArrayList();
            list = t.ret(a, b);
            for (int i = 0; i < list.size(); i++) {
                //System.out.println(list.get(i));
                System.out.println(Arrays.toString((int[])list.get(i))); //因为list保存的是数组对象，所以调用数组对象的toString方法打印数组元素
        }
    }
    public List<int[]> ret(int[] a, int b) {
        List list = new ArrayList();
        for (int i = 0; i < a.length; i++) {
            for (int j = 1 + i; j < a.length; j++) {
                if (a[i] + a[j] == b) {
                    //list.add(a[i], a[j]);
                    list.add(new int[]{i, j}); //这里要保存为数组，按题目要求输出下标，如果要输出元素怎改为new int[]{a[i], a[j]}
                }
            }
        }
        return list;
    };