/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* reverseList(ListNode* head) {
if(head==NULL||head->next==NULL) return head;
ListNode* cur=head;
ListNode* p=NULL;
ListNode* temp=cur->next;
while(temp!=NULL){
cur->next=p;
p=cur;
cur=temp;
temp=temp->next;
}
cur->next=p;
return cur;
}
};
逐位向前反转next指针