OOP & Design Patterns - Command Pattern - Undo/Redo, Request Queuing & Logging
What is the time complexity per operation (execute, undo, or redo) in the brute force Command Pattern implementation that uses manual undo and redo stacks for n commands?
What is the time complexity per operation (execute, undo, or redo) in the brute force Command Pattern implementation that uses manual undo and redo stacks for n commands?
medium🪤 Complexity Trap Q13 of Q15
Step-by-Step Solution
Solution:
Step 1: Identify operations involved per command
Each execute, undo, or redo involves pushing or popping a command from a stack and calling execute or undo on that command.Step 2: Analyze time per operation
Stack push/pop and command execute/undo are O(1) operations, so total per operation is O(1).Final Answer:
Option D -> Option DQuick Check:
Stacks and command calls are constant time [OK]
Quick Trick: Undo/redo stacks enable O(1) per operation [OK]
Common Mistakes:
MISTAKES- Assuming undo scans entire history
- Confusing stack operations with linear scans
Trap Explanation:
PITFALL- Many think undo requires scanning or copying stacks, but stacks allow O(1) push/pop.
Interviewer Note:
CONTEXT- Tests understanding of data structure operations and their impact on complexity.
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