[LeetCode]Reverse Linked List

 1 /**
 2  * Definition for singly-linked list.
 3  * struct ListNode {
 4  *     int val;
 5  *     ListNode *next;
 6  *     ListNode(int x) : val(x), next(NULL) {}
 7  * };
 8  */
 9 class Solution {
10 public:
11     ListNode* reverseList(ListNode* head) {
12         if (head == NULL ) return head;
13         
14         ListNode dummy(-1);
15         dummy.next = head;
16         
17         ListNode *prev = dummy.next;
18         ListNode *cur = prev->next;
19         while (cur != NULL) {
20             prev->next = cur->next;
21             cur->next = dummy.next;
22             dummy.next = cur;
23             cur = prev->next;
24         }
25         
26         return dummy.next;
27     }
28 };