DLL Operation: Prepend

  • Trace the basic operations of a (doubly) linked-list implementation.
  • Understand the basic operations of a (doubly) linked list well enough to implement them.

Suppose we have the following DLL, and we want to add a new node to its front.

Exercise Complete the implementation of the addFirst method that creates a node and adds it to the front of the list.

public void addFirst (T data) {
  // TODO Implement Me!
}

Hint: Use the following visualization as a guidance:

Solution
public void addFirst(T data) {
  Node<T> node = new Node<>(data);
  node.next = head;
  head.prev = node;
  head = node;
}

Caution: the implementation above fails to account for edge cases!