反转单向链表 (java 语言实现)

/**
* 演示翻转链表的两种典型实现，使用泛型。
*
* @author shan
* @create 2016-09-01 11:46
*/
public class ReverseSinglyList {

/**
* 递归，在反转当前节点之前先反转后续节点
* @param current
* @param <E>
* @return
*/
public static <E> Node<E>  reverse(Node<E> current){
if (current == null || current.getNextNode() == null){
return current;
}

Node<E> newHead = reverse(current.getNextNode());

current.getNextNode().setNextNode(current);
current.setNextNode(null);
return newHead;
}

/**
* 迭代，将当前节点的下一个节点缓存后更改当前节点指针
* @param current
* @param <E>
* @return
*/
public static <E> Node<E> reverse2(Node<E> current){
if (current == null) {
return current;
}

Node<E> pre = current;
Node<E> cur = current.getNextNode();

while(cur != null){
Node<E> tmp = cur.getNextNode();
cur.setNextNode(pre);
pre = cur;
cur = tmp;
}

current.setNextNode(null);

return pre;
}

/**
* 顺序打印链表中的值
* @param current
* @param <E>
*/
public static  <E> void printList(Node<E> current){
while(current != null){
System.out.print(current.getRecord());
current = current.getNextNode();
}
System.out.println();
}

@Test
public void testReverse() {
Node<Integer> head = new Node< Integer>(0);
Node<Integer> cur = head;
Node<Integer> tmp;
for (int i=1 ; i < 10;i++){
tmp = cur;
cur.setNextNode(new Node<Integer>(i));
cur = tmp.getNextNode();
}
printList(head);
Node<Integer> newHead = reverse(head);
printList(newHead);
}

@Test
public void testReverse2(){
Node<Integer> head = new Node< Integer>(0);
Node<Integer> cur = head;
Node<Integer> tmp;
for (int i=1 ; i < 10;i++){
tmp = cur;
cur.setNextNode(new Node<Integer>(i));
cur = tmp.getNextNode();
}

printList(head);
Node<Integer> newHead = reverse2(head);
printList(newHead);
}
}