LeetCode/cs/delete-the-middle-node-of-a-linked-list.cs

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     public int val;
 *     public ListNode next;
 *     public ListNode(int val=0, ListNode next=null) {
 *         this.val = val;
 *         this.next = next;
 *     }
 * }
 */
public class Solution {
    private int Count(ListNode node) {
        var count = 0;

        for (; node != null; node = node.next) {
            ++count;
        }

        return count;
    }

    public ListNode DeleteMiddle(ListNode head) {
        if (head == null) {
            return null;
        }

        var count = Count(head);
        if (count == 1) {
            return null;
        }

        var mid = count >> 1;

        var node = head;
        for (var i = 0; i < mid - 1; ++i) {
            node = node.next;
        }
        node.next = node.next.next;

        return head;
    }
}