Leetcode题解 206. Reverse Linked List

/**
* Definition for singly-linked list.
* public class ListNode {
*     int val;
*     ListNode next;
*     ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode reverseList(ListNode head) {
if(head==null){
return null;
}else if(head.next==null){
return head;
}
ListNode prev,last;
prev=head;
head=head.next;
prev.next=null;
if(head.next==null){
head.next=prev;
}else{
last=head.next;
while(last!=null){
head.next=prev;
prev=head;
head=last;
last=last.next;
}
head.next=prev;
}
return head;
}
}