problem_2095.java

/*2095. Delete the Middle Node of a Linked List
You are given the head of a linked list. Delete the middle node, and return the head of the modified linked list.
The middle node of a linked list of size n is the ⌊n / 2⌋th node from the start using 0-based indexing, where ⌊x⌋ denotes the largest integer less than or equal to x.
    For n = 1, 2, 3, 4, and 5, the middle nodes are 0, 1, 1, 2, and 2, respectively.
*/

class Solution {
    public ListNode deleteMiddle(ListNode head) {
        if (head.next == null) {
            return null;
        }
        ListNode slow = head;
        ListNode fast = head;
        ListNode prev = null;
        while (fast != null && fast.next != null) {
            prev = slow;
            slow = slow.next;
            fast = fast.next.next;
        }
        prev.next = slow.next;
        return head;
    }
}