reverse k nodes snip

node* reverse_K_nodes(node* head, int k){
    node* current = head;
    node* next = NULL;
    node* prev = NULL;

    while(current != NULL && k--){
        next = current->getNextNode();
        current->updateLink(prev);
        prev = current;
        current = next;
    }
    head = prev;
    current = head;
    while(current->getNextNode() != NULL){
        current = current->getNextNode();
    }
    current->updateLink(next);
    return head;
}