反轉單向鏈表 (java 語言實現)

/**
 * 演示翻轉鏈表的兩種典型實現，使用泛型。
 *
 * @author shan
 * @create 2016-09-01 11:46
 */
public class ReverseSinglyList {

    /**
     * 遞歸，在反轉當前節點之前先反轉後續節點
     * @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，將當前節點的下一個節點緩存後更改當前節點指針
     * @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;
    }


    /**
     * 順序打印鏈表中的值
     * @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);
    }
}