public class Sykli {

    public static int sykli(Node alku) {
        if (alku == null) {
            return 0;
        }
        Node eka = alku;
        Node toka = alku;
        boolean samat = false;
        while (eka != null && toka != null) {
            eka = eka.getNext();
            toka = toka.getNext();
            if (toka != null) {
                toka = toka.getNext();
            }
            if (eka == toka) {
                samat = true;
                break;
            }
        }
        if (samat) {
            int pituus = 1;
            eka = eka.getNext();
            while (eka != toka) {
                eka = eka.getNext();
                pituus++;
            }
            return pituus;
        }
        return 0;
    }

    public static void main(String[] args) {
        Node vika = new Node(900);
        Node sykli = new Node(7, new Node(5, new Node(6, vika)));
        Node lista = new Node(1, new Node(2, new Node(3, sykli)));

        System.out.println("Syklitön: " + sykli(lista));

        vika.setNext(sykli);

        System.out.println("Syklillinen: " + sykli(lista));
    }
}