Question

In java

1. Write a sequence of commands that will remove the tail of a doubly linked list.

Using a linked list with 3 nodes, draw what happens to the list as each line executes when you remove the tail.

2. Write a sequence of commands that will add a new item to index 0 of a doubly linked list.

Using a linked list with 3 nodes, draw what happens to the list as each line executes.

Answer 1

1)

if(head == null) {

return;

}

if (head != tail) {

tail = tail.prev;

tail.next = null;

} else {

head = tail = null;

}

2)

Node newNode = new Node(value);

newNode.next = head;

newNode.prev = null;

if (head != null)

        head.prev = newNode;

head = newNode;