2095. Delete the Middle Node of a Linked List

/**
 * 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* slow = head;
        ListNode* fast = head -> next;
        ListNode* prev = NULL;

        if(head == NULL || head -> next == NULL)
            return NULL;

        while(slow != NULL && fast != NULL)
        {
            fast = fast -> next;
            if(fast != NULL)
                fast = fast -> next;
            prev = slow;
            slow = slow -> next;
        }

        prev -> next = slow -> next;

        return head;
        
    }
};