206. 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
代码
class Solution {
public:
ListNode* reverseList(ListNode* head) {
ListNode* pre = NULL;
ListNode* cur = head;
ListNode* fut;
while (cur != NULL) {
fut = cur->next;
cur->next = pre;
pre = cur;
cur = fut;
}
return pre;
}
};