/**

* author : wangjinlei

* email : sea11107@mail.ustc.edu.cn

*/

class Node {

public int data;

public Node next;

public Node(int data) {

this.data = data;

this.next = null;

}

}

class LinkedList {

public Node head;

public LinkedList() {

head = null;

}

// insert a node at the head of the list

public LinkedList append(Node node) {

node.next = head;

this.head = node;

return this;

}

// an elegant way to print the list

public String toString() {

StringBuilder sbuf = new StringBuilder();

for (Node begin= this.head; begin != null; begin = begin.next) {

sbuf.append(begin.data).append(",");

}

return sbuf.toString();

}

public void reverse() {

if (this.head == null)

return;

this.head = reverseHelper(null, head, head.next);

}

private Node reverseHelper(Node t, Node p, Node q) {

p.next = t;

return (q == null) ? p : reverseHelper(p, q, q.next);

}

}

public class Reversor {

public static void main(String[] args) {

LinkedList list = new LinkedList();

list.append(new Node(1)).append(new Node(2));//.append(new Node(3)).append(new Node(4));

System.out.println(list);

list.reverse();

System.out.println(list);

}

}