class Solution {
public:
ListNode* reverseList(ListNode* head) {
if (head == NULL || head->next == NULL) return head;
ListNode * p = head->next;
head->next = NULL;
while(NULL!=p)
{
ListNode *tmp = p->next;
p->next = head;
head = p;
p = tmp;
}
return head;
}
};
struct ListNode* reverseListRe(struct ListNode* head) {
if(NULL==head||NULL==head->next) return head;
struct ListNode *p=head->next;
head->next=NULL;
struct ListNode *newhead=reverseListRe(p);
p->next=head;
return newhead;
}