import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    public ListNode middleNode(ListNode head) {
        // write code here
        ArrayList<ListNode> arr = new ArrayList<>();
        ListNode node = head;
        while (null != node) {
            arr.add(node);
            node = node.next;
        }
        return arr.get(arr.size() / 2);
    }
}