Java实现单链表反转

本文主要介绍单链表反转的两种方法，记录如下：

1.

package com.leetcode;public class ListReverse {public static void main(String[] args) {Node node1 = new Node(1);Node node2 = new Node(2);Node node3 = new Node(3);Node node4 = new Node(4);node1.next = node2;node2.next = node3;node3.next = node4;Node head = reverse(node1);while(head != null){System.out.println(head.val);head = head.next;}}public static Node reverse(Node head){Node cur = head, post = head.next;head.next = null;while(post != null){Node tmp = post;post = post.next;tmp.next = cur;cur = tmp;}return cur;}static class Node{int val;Node next;Node(int val){this.val = val;this.next = null;}}}

运行结果为：

4321

2.

package com.leetcode;public class ListReverse {public static void main(String[] args) {Node node1 = new Node(1);Node node2 = new Node(2);Node node3 = new Node(3);Node node4 = new Node(4);node1.next = node2;node2.next = node3;node3.next = node4;Node head = reverse(node1);while(head != null){System.out.println(head.val);head = head.next;}}public static Node reverse(Node head){Node dummy = new Node(-1);dummy.next = head;Node pre = dummy, cur = head, post = head.next;while(post != null){cur.next = post.next;post.next = pre.next;pre.next = post;post = cur.next;}return dummy.next;}static class Node{int val;Node next;Node(int val){this.val = val;this.next = null;}}}

运行结果为：

4321