Java练习题，可能是循环，第三个，大家帮我看看

Question

Answer 1

public class Test {
    public void print(int lineSum) {
        int sum = (lineSum + 1) * lineSum / 2;
        int p = 0;
        List<List<Integer>> lists = new ArrayList<>();
        //  1  2  -1  -2
        int dir = 1;
        int line = -1;
        while (p++ < sum) {
            line += dir > 0 ? 1 : (dir == -1 ? -1 : 0);
            if (line >= lists.size()) {
                List<Integer> list = new LinkedList<>();
                list.add(p);
                lists.add(list);
                dir = dir == 1 ? 2 : -1;
            } else {
                lists.get(line).add(p);
                dir = dir > 0 ? dir : (dir == -1
                        ? (line == 0 ? -2 : -1)
                        : 1);
            }
        }

        printVals(lists);
    }

    public static void main(String[] args) {
        Test solution = new Test();
        solution.print(10);
    }
}

输出示例