Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Example—two sum:** Brute O(n²) time, O(1) space. Optimized O(n) time, O(n) space (hash map). **Merge intervals:** Sort O(n log n) time, O(1) or O(n) space. **Always state both.** **Production:** Choose from input size; optimize when profiling shows bottleneck. Document in...
Example—two sum: Brute O(n²) time, O(1) space. Optimized O(n) time, O(n) space (hash map). Merge intervals: Sort O(n log n) time, O(1) or O(n) space. Always state both. Production: Choose from input size; optimize when profiling shows bottleneck. Document in comments. Cost: Space vs time trade-off—hash uses memory for speed.
Pro-Move: Tie complexity to real input sizes. Red Flag: Optimizing prematurely without profiling.
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