Delete a Node


Problem Statement :


Delete the node at a given position in a linked list and return a reference to the head node. The head is at position 0. The list may be empty after you delete the node. In that case, return a null value.

Example:
list=0->1->2->3
position=2

After removing the node at position 2, list'= 0->1->-3.


Function Description:

Complete the deleteNode function in the editor below.

deleteNode has the following parameters:
- SinglyLinkedListNode pointer llist: a reference to the head node in the list
- int position: the position of the node to remove

Returns
- SinglyLinkedListNode pointer: a reference to the head of the modified list


Input Format:

The first line of input contains an integer n, the number of elements in the linked list.
Each of the next n lines contains an integer, the node data values in order.
The last line contains an integer, position, the position of the node to delete.


Constraints:
     1.  1<=n<=1000
     2.  1<=list[i]<=1000



Solution :



title-img


                            Solution in C :

In C:

//the following function is all that is needed to complete
// the challenge in hackerrank platform.

SinglyLinkedListNode* deleteNode(SinglyLinkedListNode* llist, int position) {
    if((position) == 0) {
        return llist->next;
    }
    llist->next = deleteNode(llist->next, position-1);
    return llist;
}









In C++:

//the following function is all that is needed to complete
//the challenge in hackerrank platform

Node* Delete(Node *head, int position)
{
  // Complete this method
    Node *prev = NULL;
    Node *ptr = head;
    
    int pos = 0;
    
    if(position==0)
    {
        head=head->next;
        delete (ptr);
    }
    else
    {
        while(position!=pos)
        {
            ++pos;
            prev=ptr;
            ptr=ptr->next;
        }
        
        if(ptr!=NULL)
        {
            prev->next=ptr->next;
            delete (ptr);
        }
    }
    return head;
}









In Java:

//the following method is all that is needed to complete the 
//challenge in hackerrank plartform

static SinglyLinkedListNode deleteNode(SinglyLinkedListNode llist, int position) {
        int currentNodePosition = 0;
        SinglyLinkedListNode head = llist;
        SinglyLinkedListNode currentNode = llist;
        
         if (position == 0) {
            head = head.next;
            return head;
        }
        
        while (currentNodePosition < position - 1) {
            currentNode = currentNode.next;
            currentNodePosition++;
        }
        
        if (currentNode.next != null && currentNode.next.next != null) {
            currentNode.next = currentNode.next.next;
        }
        
        return head;
    }










In Python 3: 

#the following method is all that is needed to complete the
#challenge in hackerrank platfrom

def Delete(head, position):
  currentPos = 0
  prevNode = None
  node = head
  while currentPos < position:
    currentPos = currentPos+1
    prevNode = node
    node = node.next

  if prevNode is not None:
      prevNode.next = node.next
      return head
  else:
      n = node.next
      node.next = None
      return n
                        








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