ReverseLinkedList.java

ReverseLinkedList.java

package kata.list.reverse;

class Node {
    int value;
    Node next;

    public Node(int value, Node next) {
        this.value = value;
        this.next = next;
    }
}

public class LinkedListReverse {

    /*
    * @params : node - a linked list
    * @output : return the reversed linked list
    */
    public static Node reverse(Node node) {

        if (node == null || node.next == null ) {
            return node;
        }

        Node prev = null;
        Node current = node;
        Node next;

        while (current.next != null) {
            next = current.next;
            current.next = prev;
            prev = current;
            current = next;
        }

        current.next = prev;
        return current;
    }

    public static void main(String args[]) {

        Node three = new Node(3, null);
        Node two = new Node(2, three);
        Node one = new Node(1, two);

        Node reversed = reverse(one);
        print(reversed);

        System.out.println();
        three = new Node(3, null);
        reversed = reverse(three);
        print(reversed);

        System.out.println();
        three = new Node(3, null);
        two = new Node(2, three);
        reversed = reverse(two);
        print(reversed);
    }

    private static void print(Node reversed) {

        Node node = reversed;

        while (node !=null) {
            System.out.print( node.value + " ");
            node = node.next;
        }

    }

}