Understanding deletion before a given node

Deleting a node before the given node is an operation that gives a doubly linked list a significant advantage over a singly linked list. In a singly linked list, the implementation of this operation is complicated as it requires keeping a previousToPrevious reference variable to delete the node before a given node.

However, in a doubly linked list, we can access the nodes in the reverse direction using the previous pointer stored in every node, making the entire operation much simpler. Let's examine all the possible cases for deleting a node before the given node in a doubly linked list.

1. The list is empty