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

[Zobeir-Rigi]

• I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
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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 caches" exercise.

Added memoisation/caching to improve the performance of:

• fibonacci
• making_change

All provided tests pass.

[cjyuan]

Could you look into an approach that doesn't require keeping the cache in the global scope?

[Zobeir-Rigi]

Could you look into an approach that doesn't require keeping the cache in the global scope?

I updated the implementation so the cache is no longer stored in the global scope.

[cjyuan]

Array and tuple creations are relatively costly operations.

We could further improve the performance if we can

• avoid repeatedly creating the same sub-arrays at line 41 (e.g. use another cache), and
• create key (on line 19) as (total, a_unique_integer_identifying_the_subarray) instead of as (total, tuple of coins)
  • There are only a small number of different subarrays. We can easily assign each subarray a unique integer.

[Zobeir-Rigi]

Array and tuple creations are relatively costly operations.

We could further improve the performance if we can

• avoid repeatedly creating the same sub-arrays at line 41 (e.g. use another cache), and

• create key (on line 19) as (total, a_unique_integer_identifying_the_subarray) instead of as (total, tuple of coins)

  • There are only a small number of different subarrays. We can easily assign each subarray a unique integer.

Thanks, I refactored the solution to avoid repeatedly creating sublists and tuples. The implementation now uses a fixed coin list and passes a start index through the recursive calls, which allows the cache key to be (total, start_index) and reduces unnecessary allocations.

[cjyuan]

Changes look good.