London | 26-SDC-March | Zobeir Rigi | Sprint 2 | Improve code with precomputing

[Zobeir-Rigi]

• I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
• My changes meet the requirements of the task
• I have tested my changes
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I originally completed all the Sprint 2 exercises in one PR, but the validation expected separate PRs for each issue. This PR contains only the "Improve code with precomputing" exercise.

Improved performance by introducing precomputing techniques in:

• common_prefix
• count_letters

All provided tests pass.

[cjyuan]

Code are correct.

Could you use complexity to explain how the new implementation is better than the original implementation?

[Zobeir-Rigi]

Code are correct.

Could you use complexity to explain how the new implementation is better than the original implementation?

Sure,
For common_prefix, the original solution compared every pair of strings, resulting in O(n²) complexity. By sorting the strings first (O(n log n)) and then comparing only neighbouring strings, the overall complexity is reduced to O(n log n).

For count_letters, the original solution checked membership in the string for every character, resulting in O(n²) complexity. The refactored version pre-computes a set of characters in O(n), allowing O(1) lookups and reducing the overall complexity to O(n).

[cjyuan]

All good.