LeetCode206-反转链表

题目

代码

/*** Definition for singly-linked list.* public class ListNode {*     int val;*     ListNode next;*     ListNode() {}*     ListNode(int val) { this.val = val; }*     ListNode(int val, ListNode next) { this.val = val; this.next = next; }* }im */
class Solution {public ListNode reverseList(ListNode head) {ListNode cur = head;ListNode pre = null;while(cur != null) {ListNode next = cur.next;cur.next = pre;pre = cur;cur = next;}return pre;}
}

结论

• 虚拟出一个pre节点很关键
• 注意停止条件
• 注意交换引用的逻辑