题干
struct ListNode* ReverseList(struct ListNode* head ) {if (head == NULL||head->next==NULL ) {return head;} else {struct ListNode* Phead=head;struct ListNode* temp=head->next;Phead->next=NULL;Phead=temp;temp=temp->next;while (temp) {Phead->next=head;head=Phead;Phead=temp;temp=temp->next;}Phead->next=head;head=Phead;}return head;
}