Given a linked list, print reverse of it using a recursive function. For example, if the given linked list is 1->2->3->4, then output should be 4->3->2->1.
Note that the question is only about printing the reverse. To reverse the list itself see this
Difficulty Level: Rookie
Algorithm:
printReverse(head) 1. call print reverse for head->next 2. print head->data
Implementation:
Java
// Java program to print reverse // of a linked list class LinkedList
{ // Head of list
Node head;
// Linked list Node
class Node
{
int data;
Node next;
Node( int d)
{
data = d;
next = null ;
}
}
// Function to print reverse of
// linked list
void printReverse(Node head)
{
if (head == null ) return ;
// Print list of head node
printReverse(head.next);
// After everything else is printed,
// Print head
System.out.print(head.data + " " );
}
// Utility Functions
// Inserts a new Node at front
// of the list.
public void push( int new_data)
{
/* 1 & 2: Allocate the Node &
Put in the data*/
Node new_node = new Node(new_data);
// 3. Make next of new Node as head
new_node.next = head;
// 4. Move the head to point
// to new Node
head = new_node;
}
// Driver code
public static void main(String args[])
{
// Create linked list 1->2->3->4
LinkedList llist = new LinkedList();
llist.push( 4 );
llist.push( 3 );
llist.push( 2 );
llist.push( 1 );
llist.printReverse(llist.head);
}
} // This code is contributed by Rajat Mishra |
Output:
4 3 2 1
Time Complexity: O(n)
Space Complexity: O(n) for call stack since using recursion
Please refer complete article on Print reverse of a Linked List without actually reversing for more details!