How to reverse a singly-linked list in blocks of some given size in O(n) time in place?

Question

I recently encounter an algorithm problem:

Reverse a singly-linked list in blocks of k in place. An iterative approach is preferred.

Answer 1

The easiest way to reverse the single linked list is as follows.

private void reverse(Node node)
{
    Node current = Node;
    Node prev = null;
    Node next = null;

    if(node == null || node.next == null)
    {
        return node;
    }

    while(current != null)
    {
        next = current.next;
        //swap
        current.next = prev;
        prev = current;
        current = next;
    }
    node.next = current;
}