206. Reverse Linked List java solutions

Reverse a singly linked list.

Hint:

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

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 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) { val = x; }
 7  * }
 8  */
 9 public class Solution {
10     public ListNode reverseList(ListNode head) {
11         if(head == null) return null;
12         ListNode newlist = new ListNode(0);
13         while(head != null){
14             ListNode tmp = new ListNode(head.val);
15             tmp.next = newlist.next;
16             newlist.next = tmp;
17             head = head.next;
18         }
19         return newlist.next;
20     }
21 }