[leetcode]206. Reverse Linked List反转链表

Reverse a singly linked list.

Input: 1->2->3->4->5->NULL
Output: 5->4->3->2->1->NULL

Follow up:

A linked list can be reversed either iteratively or recursively. Could you implement both?

 

题意：

如题

 

思路：

无

 

代码：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode reverseList(ListNode head) {
            ListNode cur = head;
            ListNode pre = null;
        while(cur!= null){
            ListNode temp = cur.next;     
            cur.next = pre;
            cur = temp;   
        }      
    }
}