class Solution {

public:

    ListNode* middleNode(ListNode* head) {

        if (head == NULL)

        {

            return nullptr;

        }

        vector<ListNode*> List;

        List.push_back(head);

        int count = ;

        while (head->next != NULL)

        {

            ListNode* n = head->next;

            List.push_back(n);

            head = head->next;

            count++;

        }

        return List[count / ];

    }

};