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Following code segment contains the description in the class comments, followed by fully working solution

/**
 * Given the head of a singly linked list, return the middle node of the linked list.
 *
 * If there are two middle nodes, return the second middle node.
 *
 * Input: head = [1,2,3,4,5]
 * Output: [3,4,5]
 * Explanation: The middle node of the list is node 3.
 */
public class MiddleNode {
    public ListNode middleNode(ListNode head) {
        ListNode p1=head;
        ListNode p2=head;
        while(p2!=null){

            p2=p2.next;
            if(p2!=null){
                p2=p2.next;
            }else{
                return p1;
            }
            p1=p1.next;
        }
        return p1;
    }
}