Questions
4 of 16
Why is insertion/deletion at the head of a Linked List O(1)?
Difficulty: 2/10
Constant-Time Head Operations
Insertion or deletion at the head of a linked list is O(1) because it requires changing only a constant number of references. There is no need to shift or traverse the remaining elements.
javascript
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Head insertion requires updating the new node's next reference and head.
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Head deletion only requires moving head to the next node.
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The operation does not depend on the number of nodes.
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Therefore, both operations are O(1).
Follow-up Questions
- What is the complexity of insertion at the tail?
- How does a doubly linked list change tail deletion?