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GO Classes DPP | PYTHON & DSA |LINKEDLIST

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A singly linked list is initialised with the sequence of values $10 \rightarrow 20 \rightarrow 30 \rightarrow 40 \rightarrow 50 \rightarrow$ NULL.

If the function tricky_delete(head, 40) is executed with the target value $X=40$, what is the integer value of the third node in the list after the function completes execution?
 

# Assume a standard Node class with 'val' and 'next' attributes
def tricky_delete(head, X):
    current = head
    if current is None or current.next is None:
        return head
    # current moves until current.next.next is the target node
    while current.next.next is not None and current.next.next.val != X:
        current = current.next
    # current now points to the node BEFORE the node to be deleted.
    if current.next.next is not None and current.next.next.val == X:
        node_to_delete = current.next
        current.next = node_to_delete.next
    return head


Value of the third node after $\textbf{tricky_delete}$ : (Numerical Answer)

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The Python function tricky_delete(head, $X$ ) is designed to find the node that appears two steps before the node containing the value $X$, and then delete the node that appears immediately after the current pointer.

Goal: Delete the node before the node with value 40 . The node before 40 is the node with value 30.

Pointer Movement: The while loop advances the current pointer until current.next.next.val == 40 .

  • This stops current at the node with value 20.

Deletion: The line current.next = node_to_delete.next (where current is 20) effectively makes the node with value 20 point directly to the node with value 40 , bypassing the node with value 30.

Final List: The resulting list is $10 \rightarrow 20 \rightarrow 40 \rightarrow 50 \rightarrow$ NULL.
Answer: The third node in the resulting list is the node with value 40.

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