Reverse Linked List

https://www.geeksforgeeks.org/delete-nth-node-from-the-end-of-the-given-linked-list/

http://edgblog.wordpress.com/2007/12/06/reversing-a-singly-linked-list-in-java/

public class ReverseList {
public static void main(String args[]) {
// build a singly linked list
// a -> b -> c -> d -> e
Node a = new Node("a");
Node b = new Node("b");
Node c = new Node("c");
Node d = new Node("d");
Node e = new Node("e");
a.next = b;
b.next = c;
c.next = d;
d.next = e;
SinglyLinkedList list = new SinglyLinkedList();
list.head = a;
System.out.println("Original list");
list.print(list.head);
list.reverse();
System.out.println("\n\nList reversed with procedural method");
list.print(list.head);
list.reverse(null, list.head);
System.out.println("\n\nList re-reversed with recursive method");
list.print(list.head);
}
}

class SinglyLinkedList {
Node head;

public void print(Node node) {
System.out.print(node);
if (node.next != null) {
System.out.print(" -> ");
print(node.next);
}
}

// procedural reverse
public void reverse() {
Node n3 = head;
Node n2 = null;
Node n1 = null;
while (n3 != null) {
n1 = n2;
n2 = n3;
n3 = n2.next;
n2.next = n1;
}
head = n2;
}

// recursive reverse
public void reverse(Node n1, Node n2) {
Node n3 = n2.next;
n2.next = n1;
if (n3 != null) {
reverse(n2, n3);
} else {
head = n2;
}
}
}

class Node {
Node next;
String value;

Node(String value) {
this.value = value;
}

public String toString() {
return value;
}

}