HackerRank - insert a node in double linked list

insertANodeinDoubleLinkedList.cpp

/*
    Insert Node in a doubly sorted linked list 
    After each insertion, the list should be sorted
   Node is defined as
   struct Node
   {
     int data;
     Node *next;
     Node *prev;
   }
*/

// test case:
// 1. list is empty
// 2. new node is before head, 
// 3. after the last one, 
// 4. or in the middle. 
Node* SortedInsert(Node *head,int data)
{
    // Complete this function
   // Do not write the main method. 
    if(head==NULL)
    {
        Node* newHead = new Node(); 
        newHead->data = data; 
        newHead->next = NULL; 
        newHead->prev = NULL; 
        
        return newHead; 
    }
    
    Node* dummyHead = new Node(); 
    
    Node* runner = head; 
    Node* prev = dummyHead; 
    prev->next = runner; 
    runner->prev = prev; 
    
    bool foundPos = false; 
    while(runner !=NULL)
    {  // increasing linked list: 2, 4, 6, insert 1, or 3, 7 
        if(data < runner->data ) 
        {
           // insert a new node between prev and runner
           Node* newNode = new Node(); 
           newNode->data = data; 
            
           prev->next = newNode; 
           newNode->prev = prev; 
           
           newNode->next = runner; 
           runner->prev = newNode; 
           
           foundPos = true; 
           break; 
        }
        
        
        prev = runner; 
        runner = runner->next; 
    }
    
    if(!foundPos)
    {
        Node* newNode = new Node(); 
        newNode->data = data; 
        
        prev->next = newNode; 
        newNode->prev = prev; 
        
        newNode->next = NULL;     
    }
    
    return dummyHead->next;  
}