# Linked list

A linked list is a data structure composed of a group of nodes, each node linking to the next node in the sequence. Each node consist of two elements, `.data`

which stores the contents of the node, and `.next`

which is a reference to the next node.

Linked lists are one of the simplest data structures. They allow for efficient insertion or removal of elements from any position in the sequence.

# Adding nodes

To add a new node with `data`

to the start of a linked list:

- Create a new node containing
`data`

- Point the
`.next`

of the new node to the current first node - Point the start of the list
`first`

to the new node

This runs in time.

# Removing nodes

To remove data from a linked list:

- If the first node
`.data`

is equal to data:- Point the start of the list to the node after the first node

- Otherwise:
- Find a node
`prev`

just before a node with`.data`

equal to data - Point
`prev.next`

to`prev.next.next`

, skipping the node being removed

- Find a node

Finding the node to remove runs in time. Removing the node runs in time. If the previous node to the node to be removed is already available, for example during iteration, then removing the node always runs in time.

This visualisation allows the adding or removal of nodes to a linked list. Use the buttons on the right of the code to trigger running the commands on the list.