Java基础之翻转单链表

/**  
 * @author luochengcheng  
 * 定义一个单链表  
 */  
class Node {   
    //变量   
    private int record;   
    //指向下一个对象   
    private Node nextNode;   
  
    public Node(int record) {   
        super();   
        this.record = record;   
    }   
    public int getRecord() {   
        return record;   
    }   
    public void setRecord(int record) {   
        this.record = record;   
    }   
    public Node getNextNode() {   
        return nextNode;   
    }   
    public void setNextNode(Node nextNode) {   
        this.nextNode = nextNode;   
    }   
}   
  
/**  
 * @author luochengcheng  
 *  两种方式实现单链表的反转(递归、普通)  
 *  新手强烈建议旁边拿着纸和笔跟着代码画图(便于理解)  
 */  
public class ReverseSingleList {   
    /**   
     * 递归，在反转当前节点之前先反转后续节点   
     */  
    public static Node reverse(Node head) {   
        if (null == head || null == head.getNextNode()) {   
            return head;   
        }   
        Node reversedHead = reverse(head.getNextNode());   
        head.getNextNode().setNextNode(head);   
        head.setNextNode(null);   
        return reversedHead;   
    }   
  
    /**   
     * 遍历，将当前节点的下一个节点缓存后更改当前节点指针   
     *    
     */  
    public static Node reverse2(Node head) {   
        if (null == head) {   
            return head;   
        }   
        Node pre = head;   
        Node cur = head.getNextNode();   
        Node next;   
        while (null != cur) {   
            next = cur.getNextNode();   
            cur.setNextNode(pre);   
            pre = cur;   
            cur = next;   
        }   
        //将原链表的头节点的下一个节点置为null，再将反转后的头节点赋给head      
        head.setNextNode(null);   
        head = pre;   
           
        return head;   
    }   
  
    public static void main(String[] args) {   
        Node head = new Node(0);   
        Node tmp = null;   
        Node cur = null;   
        // 构造一个长度为10的链表，保存头节点对象head      
        for (int i = 1; i < 10; i++) {   
            tmp = new Node(i);   
            if (1 == i) {   
                head.setNextNode(tmp);   
            } else {   
                cur.setNextNode(tmp);   
            }   
            cur = tmp;   
        }   
        //打印反转前的链表   
        Node h = head;   
        while (null != h) {   
            System.out.print(h.getRecord() + " ");   
            h = h.getNextNode();   
        }   
        //调用反转方法   
        head = reverse2(head);   
        System.out.println("\n**************************");   
        //打印反转后的结果   
        while (null != head) {   
            System.out.print(head.getRecord() + " ");   
            head = head.getNextNode();   
        }   
    }   
}