1. public class DMSList {
    2.     private IntNode head;
    4.     DMSList() {
    5.         this.head = new IntNode(-1000, new LastIntNode());
    6.     }
    8.     public class IntNode {
    9.         IntNode next;
    10.         int val;
    12.         IntNode(int val, IntNode next) {
    13.             this.val = val;
    14.             this.next = next;
    15.         }
    17.         public int max() {
    18.             return Math.max(val, next.max());
    19.         }
    20.     }
    22.     public class LastIntNode extends IntNode {
    24.         LastIntNode() {
    25.             super(0, null);
    26.         }
    28.         @Override
    29.         public int max() {
    30.             return 0;
    31.         }
    32.     }
    34.     public int max() {
    35.         return head.next.max();
    36.     }
    38.     public void insertFront(int x) {
    39.         head.next = new IntNode(x, head.next);
    40.     }
    42.     public static void main(String[] args) {
    43.         DMSList a = new DMSList();
    44.         a.insertFront(0);
    45.         a.insertFront(2);
    46.         a.insertFront(7);
    47.         a.insertFront(5);
    49.         System.out.println(a.max());
    50.     }
    51. }