List<Integer>倒叙排列的方法

List<Integer> scoreList

Collections.reverse(scoreList);//倒叙排列

//倒序求和
 private static Integer sum3Num(List<Integer> scoreList) {
        scoreList.sort(Integer::compareTo);

        int size = scoreList.size();
        int sum = 0;
        for (int i = size - 1; i >= size - 3; i--) {
            sum = sum + scoreList.get(i);
        }
        return sum;
    }

scoreList.stream().sorted(Comparator.reverseOrder());

private static Integer sum3Num(List<Integer> scoreList) {
//        Collections.reverse(scoreList);//倒叙排列
        scoreList.stream().sorted(Comparator.reverseOrder());
        List<Integer> newList = scoreList.subList(0, 3);
        return newList.stream().mapToInt(a -> a).sum();
    }

最大的前3项求和