public class Piramide {

 

    public static void print(LinkedList<Integer> list, int n) {

        StringBuilder sb = new StringBuilder();

        Iterator<Integer> it;

        if (n == 0) {

            it = list.descendingIterator();

        } else {

            it = list.iterator();

        }

        while (it.hasNext()) {

            sb.append(it.next()).append("-");

        }

        sb.deleteCharAt(sb.length() - 1);

        System.out.println(sb.toString());

    }

 

    public static void main(String[] args) {

        int n = 6;

        System.out.printf("n = %d\n", n);

 

        LinkedList<Integer> list = new LinkedList<Integer>();

 

        for (int i = 1; i <= n; i++) {

            list.add(i);

            print(list, i & 1);

        }

    }

}