翻转链表 - C++

class Solution {
public:
    /**
     * @param head: The first node of linked list.
     * @return: The new head of reversed linked list.
     */
    ListNode *reverse(ListNode *head) {
        ListNode *first=NULL;
        while(head!=NULL)
        {
            ListNode *first1;
            first1=head->next;
            head->next=first;
            first=head;
            head=first1;
            
        }
        return first;
        // write your code here
    }
};

水.