Reverse a linked list-hackerrank-algorithm-solution

You’re given the pointer to the head node of a linked list. Change the next pointers of the nodes so that their order is reversed. The head pointer given may be null meaning that the initial list is empty.

Input Format
You have to complete the Node* Reverse(Node* head) method which takes one argument - the head of the linked list. You should NOT read any input from stdin/console.

Output Format
Change the next pointers of the nodes that their order is reversed and return the head of the reversed linked list. Do NOT print anything to stdout/console.

Sample Input

NULL
2 --> 3 --> NULL

Sample Output

NULL

3 --> 2 --> NULL

Explanation
1. Empty list remains empty
2. List is reversed from 2,3 to 3,2

c++ program:

/*

  Reverse a linked list and return pointer to the head

  The input list will have at least one element  

  Node is defined as 

  struct Node

  {

     int data;

     struct Node *next;

  }

Reverse(Node  head)

        prev=NULL       //Previous Pointer

        cur=head        //Current Node

        nxt=*cur.next   //Next Pointer

        while cur is not NULL

            nxt=(*cur).next

            (*cur).next=prev

            prev=cur

            cur=nxt

        head=prev

        return head

*/

Node* Reverse(Node *head)

{

 struct Node *prev=NULL,*cur,*nxt;

    cur=head;

    nxt=cur->next;

    while(cur!=NULL)

        {

        nxt=cur->next;

    cur->next=prev;

    prev=cur;

    cur=nxt;

    }

    head=prev;

    return(head);

    // Complete this method

}