JZ反转链表

　　反转链表题目描述输入一个链表，反转链表后，输出新链表的表头。
　　题目链接: 反转链表(https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca?tpId=13&&tqId=11168&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking)代码/**  * 标题：反转链表  * 题目描述  * 输入一个链表，反转链表后，输出新链表的表头。  * 题目链接：  * https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca?tpId=13&&tqId=11168&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking  */ public class Jz15 {      public ListNode reverseList(ListNode head) {         if (head == null || head.next == null) {             return head;         }         ListNode first = head, second = head.next;         first.next = null;         while (first != null && second != null) {             ListNode temp = first;             first = second;             second = second.next;             first.next = temp;         }         return first;     }      public static void main(String[] args) {         ListNode head = new ListNode(1);         head.next = new ListNode(2);         head.next.next = new ListNode(3);         System.out.println(＂before reverse＂);         ListNode cur = head;         while (cur != null) {             System.out.print(cur.val + ＂ ＂);             cur = cur.next;         }         System.out.println();         Jz15 jz15 = new Jz15();         ListNode result = jz15.reverseList(head);         System.out.println(＂after reverse＂);         ListNode cur1 = result;         while (cur1 != null) {             System.out.print(cur1.val + ＂ ＂);             cur1 = cur1.next;         }     } }
　　【每日寄语】 生活的本质就是幸福的活着，而生活的智慧就是活出自己想要的样子。