【LeetCode】206. Reverse Linked List

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* reverseList(ListNode* head) {
if(head == NULL) return NULL;
ListNode* ptr = NULL;
while(head !=NULL)
{
ListNode* L = new ListNode(head->val);
L->next = ptr;
ptr = L;
head = head->next;
}
return ptr;
}
};