文章目录
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。
三指针
/**
* 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 left=head;
ListNode right=null;
if(left!=null){
right=head.next;
}else{
right=null;
}
ListNode end=null;
while(left!=null){
//更改链接方向
left.next=end;
//全指针右移
end=left;
left=right;
if(right!=null)
right=right.next;
}
return end;
}
}