public static List<int[]> combin(final int TOTAL, final int SELETED) {        List<int[]> list = new ArrayList<int[]>(400000);        int[] i = new int[SELETED];        for (int x = 1; x <= SELETED; x++)            i[x - 1] = x;        final int LAST = SELETED - 1;        while (true) {            list.add(Arrays.copyOf(i, SELETED));            i[LAST]++;            for (int n = LAST; n > 0; n--) {                //i[n]达到顶点                if (i[n] > TOTAL - SELETED + 1 + n) {                    i[n - 1]++;                    for (int x = n; x < SELETED; x++) {                        i[x] = i[x - 1] + 1;                    }                }            }            if (i[0] == TOTAL - LAST + 1) {                break;            }        }        return list;        // return null;    }    public static void main(String[] args) {        long i = System.currentTimeMillis();        List<int[]> list = combin(36, 5);        System.out.println(System.currentTimeMillis() - i);        System.out.println(list.size());    }