/**
 * 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* deleteMiddle(ListNode* head) {

           ListNode* o=head;
           ListNode* t=head;
           ListNode* prev=head;
           if(head->next==NULL)
           {
            return head=NULL;
           }
           if(head->next->next==NULL)
           {
            delete head->next;
            head->next=NULL;
            return head;
           }
          while(t!=NULL && t->next!=NULL) 
           {
             if(t!=head)
             prev=prev->next;
             o=o->next;
             t=t->next->next; 
           }
           prev->next=o->next;
           delete o;
        return head;
    }
};