1.java

import java.util.*;

class Main {
    static class Node {
        int data;
        Node prev, next;
        Node(int data) { this.data = data; }
    }

    static class DoublyLinkedList {
        Node head;

        void append(int data) {
            Node newNode = new Node(data);
            if (head == null) { head = newNode; return; }
            Node temp = head;
            while (temp.next != null) temp = temp.next;
            temp.next = newNode;
            newNode.prev = temp;
        }

        void sort() {
            List<Integer> vals = new ArrayList<>();
            for (Node t = head; t != null; t = t.next) vals.add(t.data);
            Collections.sort(vals);
            head = null;
            for (int v : vals) append(v);
        }

        void print() {
            for (Node t = head; t != null; t = t.next) {
                System.out.print(t.data);
                if (t.next != null) System.out.print(" <-> ");
            }
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        DoublyLinkedList dll = new DoublyLinkedList();
        for (int i = 0; i < n; i++) dll.append(sc.nextInt());
        dll.sort();
        dll.print();
    }
}