2095. Delete the Middle Node of a Linked List.cpp

/**
 * 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) {
        if(head == nullptr || head->next==nullptr) return nullptr;
        
        ListNode* slow = head,*fast = head;
        while(fast!=nullptr && fast->next!= nullptr){
            slow = slow->next;
            fast = fast->next->next;
        }

        ListNode *temp = head;
        while(temp->next != slow) temp = temp->next;
        temp->next = temp->next->next;
        return head;
    }
};