Question

Suppose head is a head reference for a linked list of integers. Write a few lines of code that will remove the second node of the list. (If the list originally had only one node, then remove that node instead; if it had no nodes, then leave the list empty.)

Answer 1

To remove the second node from a linked list, check if the head is not null and if there's only one node, set head to null; otherwise, bypass the second node by setting head.next to head.next.next.

Step-by-step explanation:

Removing a node from a linked list is a common operation in data structures, which is often covered in computer science curriculum. The provided scenario requires writing a few lines of code to remove the second node of a linked list, and the operation varies based on the number of nodes in the list. Here is how one might write that code in a generic way:

if (head != null) {
if (head.next == null) {
head = null; // Remove the only node if that's all there is.
} else {
head.next = head.next.next; // Bypass the second node.
}
}

In the given code, we check if the head is not null, meaning the list is not empty. If there's only one node present (head.next is null), we simply set the head to null. If there are at least two nodes, we update the head.next reference to point to the node after the second one (head.next.next), effectively removing the second node from the list.