Fast local changes
Once you have the right node, inserting or removing its neighbor can be O(1).
Linked Lists
5 chapters · 9 challenges · The Chain Causeway
Understand the idea, practise through play, then prove it in code. Choose your next quest below.
Visual introduction to this topic
Start here · 3 minute mental model
What is a linked list?
A linked list is a chain of nodes. Each node stores a value and a link to the next node. Unlike an array, the nodes do not need to sit beside each other in memory.
Think of a treasure hunt. Each clue contains a reward and tells you where the next clue is. You can reach clue three only by following clues one and two.
Traversal follows next links from head until null.
Sequential access
Finding position k takes O(k), because there is no instant index jump.
Protect the next link
Save a node's next reference before rewiring, or the unexplored suffix can disappear.
What you will learn firstThe Vanishing Link
Begin the guided lesson Bypass one node without breaking the chain
01
Pointer Rewiring
0/2 completePractice pointer rewiring through 2 visual expeditions.
02
Fast And Slow
0/2 completePractice fast and slow through 2 visual expeditions.
03
Dummy Head
0/2 completePractice dummy head through 2 visual expeditions.
04
Merge
0/1 completePractice merge through 1 visual expedition.
05
Reversal
0/2 completePractice reversal through 2 visual expeditions.
Source reviewed
Built from authoritative material
This track is checked against the sources below. Visual traces still carry their own complete or guided coverage label, so unfinished explanations are not presented as complete executions.