Reverse a Linked List in groups of given size

Given a linked list, write a function to reverse every k nodes (where k is an input to the function).

Example:
Inputs:  1->2->3->4->5->6->7->8->NULL and k = 3 
Output:  3->2->1->6->5->4->8->7->NULL. 

Solution : Reverse a LinkedList keeping counter, to keep node count along with it.


Algo :

1. Cur = Head, Next = Null, Pre = Null
2. While (Curr != NULL AND Counter < k ) //till the end & counter to keep less than input k
1. next = cur -> nextt
2. cur-> nextt = pre 
3. pre = cur
4. cur = next
5. count ++;
3. if ( next !=  NULL)
1.  head->next = reverse(next, k); 
4. return prev;

Step 2  : is to reverse a linked list. by keeping K set we are reversing only first K node.

Step 3  : is to reverse next k node, 

so till the end of linked list we are reversing each k nodes.

Step 4  : prev will be head of this linkedlist, return it.