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 :
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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