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What is the difference between ArrayList and LinkedList?
JavaCollectionsArrayListLinkedList
Question
Compare ArrayList and LinkedList in Java. When would you use each?
Answer
ArrayList:
- Dynamic array implementation
- Random access (O(1))
- Insertion/Deletion at end: O(1) amortized
- Insertion/Deletion in middle: O(n)
- Better for frequent access
LinkedList:
- Doubly linked list implementation
- Sequential access (O(n))
- Insertion/Deletion: O(1) if position known
- Better for frequent insertions/deletions
When to Use:
- Use ArrayList when you need frequent random access
- Use LinkedList when you need frequent insertions/deletions
Explanation
The choice depends on your access patterns. ArrayList is generally preferred for most use cases due to better cache locality and lower memory overhead.