03_反转链表

反转链表

给你单链表的头节点 head ,请你反转链表,并返回反转后的链表。力扣题目链接

示例 1:

img

输入:head = [1,2,3,4,5]
输出:[5,4,3,2,1]

示例 2:

img

输入:head = [1,2]
输出:[2,1]

示例 3:

输入:head = []
输出:[]

提示:

  • 链表中节点的数目范围是 [0, 5000]
  • -5000 <= Node.val <= 5000

思路:直接反转

/**
 * 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; }
 * }
 */
class Solution {
    public ListNode reverseList(ListNode head) {
        ListNode pre = null;
        ListNode cur = head;
        while (cur != null) {
           ListNode temp = cur.next;
           cur.next = pre;
           pre = cur;
           cur = temp;
        }
        return pre;
    }
}
posted @ 2023-10-25 21:59  鲍宪立  阅读(14)  评论(0)    收藏  举报