Reverse Linked List

 I keep seeing an advertisement saying "you may know how to reverse a linked list, but not system design", so just try to write down how to reverse linked list here.

public class LinkedList {

Node head;

public static void printLinkedList(Node node) {

while(node != null) {

System.out.print(node.value + " ");

node = node.next;

}

}

public static Node reverseLinkedList(Node node) {

Node pre = null;

Node next = null;

Node cur = node;

while(cur != null) {

next = cur.next;

cur.next = pre;

pre = cur;

cur = next;

}

return pre;

}

public static void main(String[] args) 

    { 

    LinkedList list = new LinkedList();

    list.head = new Node(85);

    list.head.next = new Node(75);

    list.head.next.next = new Node(55);

    list.head.next.next.next = new Node(11);

    

    System.out.println("Order before reversing:");

    printLinkedList(list.head);

    System.out.println("Order after reversing:");

    printLinkedList(reverseLinkedList(list.head));

    } 

}

class Node {

int value;

Node next;

public Node(int value) {

this.value = value;

this.next = null;

}

}