java reverse a linked list code example

Example 1: how to reverse a linked ist

class LinkedList { 
  
    static Node head; 
  
    static class Node { 
  
        int data; 
        Node next; 
  
        Node(int d) 
        { 
            data = d; 
            next = null; 
        } 
    } 
  
    /* Function to reverse the linked list */
    Node reverse(Node node) 
    { 
        Node prev = null; 
        Node current = node; 
        Node next = null; 
        while (current != null) { 
            next = current.next; 
            current.next = prev; 
            prev = current; 
            current = next; 
        } 
        node = prev; 
        return node; 
    } 
  
    // prints content of double linked list 
    void printList(Node node) 
    { 
        while (node != null) { 
            System.out.print(node.data + " "); 
            node = node.next; 
        } 
    } 
  
    public static void main(String[] args) 
    { 
        LinkedList list = new LinkedList(); 
        list.head = new Node(85); 
        list.head.next = new Node(15); 
        list.head.next.next = new Node(4); 
        list.head.next.next.next = new Node(20); 
  
        System.out.println("Given Linked list"); 
        list.printList(head); 
        head = list.reverse(head); 
        System.out.println(""); 
        System.out.println("Reversed linked list "); 
        list.printList(head); 
    } 
}

Example 2: reverse a linked list

class recursion { 
	static Node head; // head of list 
	static class Node { 
		int data; 
		Node next; 
		Node(int d) 
		{   data = d; 
			next = null; 	} } 
	static Node reverse(Node head) 
	{ 
		if (head == null || head.next == null) 
			return head; 
		/* reverse the rest list and put the first element 
        at the end */
		Node rest = reverse(head.next); 
		head.next.next = head; 
		/* tricky step -- see the diagram */
    	head.next = null; 
		/* fix the head pointer */
		return rest; 
	}  /* Function to print linked list */
	static void print() 
	{ 
		Node temp = head; 
		while (temp != null) { 
			System.out.print(temp.data + " "); 
			temp = temp.next; 
		} 
		System.out.println(); 
	} 
	static void push(int data) 
	{ 
		Node temp = new Node(data); 
		temp.next = head; 
		head = temp; 
	} /* Driver program to test above function*/
public static void main(String args[]) 
{ 
	/* Start with the empty list */
	push(20); 
	push(4); 
	push(15); 
	push(85); 
	System.out.println("Given linked list"); 
	print(); 
	head = reverse(head); 
	System.out.println("Reversed Linked list"); 
	print(); 
} } // This code is contributed by Prakhar Agarwal

Example 3: revese the linked list java

Easiest way


public static LinkedList reverse(LinkedList head) {
		LinkedList prevAddress = null;
		LinkedList currentAddress = head;
		LinkedList nextAddress = head.next;
		
		while(nextAddress!=null) {
			currentAddress.next = prevAddress;
			prevAddress = currentAddress;
			currentAddress = nextAddress;
			nextAddress= currentAddress.next;
			currentAddress.next = prevAddress;
		}
		head = currentAddress;
		return head;
	}
    
Just try to visualize its all about pointers game. :-)
  NO GFG ANSWER