public class FrogAction {

    private short n;
    private short[] comars;
    private TreeSet<Integer> set = new TreeSet<>();

    public FrogAction(short n, short[] comars) {
        this.n = n;
        this.comars = comars;
    }

    public TreeSet<Integer> getSet() {
        return set;
    }

    public void next(int index, int sum) {
        if (index == n - 1) {
            sum += comars[index];
            set.add(sum);
        } else if (index < n - 1) {
            sum += comars[index];
            next( index + 2, sum);
            next( index + 3, sum);
        }
    }
}