53.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。
/**
* 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 cur = null;
ListNode pre = head;
while(pre != null) {
ListNode temp = pre.next;
pre.next = cur;
cur = pre;
pre = temp;
}
return cur;
}
}