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。
示例 1:
输入:head = [1,2,3,4,5]
输出:[5,4,3,2,1]
示例 2:
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
int main() { auto a1 = ListNode(1); auto a2 = ListNode(2); auto a3 = ListNode(3); auto a4 = ListNode(4); auto a5 = ListNode(5); a1.next = &a2; a2.next = &a3; a3.next = &a4; a4.next = &a5; reverseList(&a1); return 0; } 这里要确保pre指针最开始赋值为空 标签:pre,head,ListNode,9.24,auto,next,链表,算法 From: https://www.cnblogs.com/minipython-wldx/p/17725836.html