Reverse Linked List

gistfile1.txt

public class Node {
  public Node next;
  public Object data;
}

public static void reverseList ( Node head) {
  if (head == null || head.next == null) {
    return;
  }

  Node before = null;
  Node current = head;

  while (current != null) {
    // move current.next to before
    Node next = current.next;
    current.next = before
    before = current;
    current = next; 
  }
  head = before;  
}


public static Node reverseWithRecursiveList ( Node head) {
  if (head == null || head.next == null) {
    return node;
  }

  Node before = head;
  Node current = head.next;
  return reverse (before, current);
}

public static Node reverse (Node before, Node current) {
   if (current == null) {
     return before;
   }
   Node next = current.next;
   current.next = before;
   before = current;
   current = next;
   return reverse (before, current);
}