Inserting a Node in a linked list using double pointers

Question

I recently saw an implementation of deleting a node from a single linked list using a double pointer . Other than making the code more beautiful does this implementation have any benefits efficiency wise . Also how can I implement a similar approach towards inserting a node to a linked list ( without keeping track of previous Node ). I am really curious if there is any better algorithm out there to achieve this

Node* Delete(Node *head, int value)
{
    Node **pp = &head; /* pointer to a pointer */
    Node *entry = head;
    while (entry ) 
    {
        if (entry->value == value)
        {
            *pp = entry->next;
        }
        pp = &entry->next;
        entry = entry->next;
    }
    return head;
}

Answer 1

Other than making the code more beautiful does this implementation have any benefits efficiency wise.

Don't have anything to compare this to so hard to say but this is about as efficient as you can remove a node from a linked list. Note that the function name Delete would be more accurate as Remove since it does not actually clean up the node it removes from the list.

Also how can I implement a similar approach towards inserting a node to a linked list ( without keeping track of previous Node ).

One way is to look ahead. Best shown in an example following the format of your Delete function.

void insert(Node *head, int value)
{
    Node *entry = head;
    while (entry)
    {
        if (entry->next == NULL)
        {
            entry->next = new Node(NULL, value);
            return;
        }
        else if (value < entry->next->value)
        {
            entry->next = new Node(entry->next, value);
            return;
        }
        entry = entry->next;
    }
}