Node structure
Each node contains a data field and a next field. The final next field stores NULL.
What is a Singly Linked List?
A singly linked list is a sequence of nodes. Each node stores data and a reference to the next node. Nodes do not need to occupy contiguous memory locations.
Add/remove headO(1)
Access/searchO(n)
Add/remove tailO(n)*
ReverseO(n)
*O(1) tail insertion is possible when a tail reference is maintained.
Edit the linked list
Use the controls to modify or inspect the list.
Current operationIdle
Nodes visited0
Comparisons / changes0
Complexity—
Linked list concepts
Head operations
Adding or removing the head changes only the head reference, so both operations take O(1).
Traversal
There is no direct index access. Reaching a position requires following links from HEAD, which takes O(n) in the worst case.
Reverse
Reversal changes every next reference so that the former tail becomes the new head. It takes O(n) time and O(1) auxiliary space.
Typical time complexities
| Operation | Time | Reason |
|---|---|---|
| Add/remove head | O(1) | Only the head reference changes. |
| Access/search | O(n) | Links are followed from HEAD. |
| Add/remove tail | O(n) | A basic singly linked list must find the last or previous node. |
| Insert/delete at known node | O(1) | Only nearby references change. |
| Reverse | O(n) | Every next reference changes once. |
| Bubble Sort | O(n²) | Adjacent values are repeatedly compared. |