West Midlands | 25-SDC-July | Gabriel Deng | Sprint 2 | Improve with precomputing

[gai93003]

No description provided.

[cjyuan]

Can you explain why your solutions are better?

[gai93003]

Yes of course, I can explain.

For count_letters, assignment, The first thing that my code improves is the precomputation of the lowercase_letters in a set. This sets time complexity to O(n) and instead of using (if letter.lower() not in s), I am using set lookup for our precomputed set making the complexity to be O(1) per lookup.
~ This improves the process especially if we are working with long strings with alot of uppercase letters.

The overall complexity is O(n) instead of O(n^2) as it was for the original code.

[gai93003]

For find_longest_common_prefix

Instead of comparing every pair of strings like in original code which gives a complexity of O(n^2 * m), I build the prefix dictionary once and then scan through it to find the longest prefix appearing alteast 2 times. This gives ~ O(1) for lookups.

The overall complexity for this solution is O(n * m^2) which is good for many short strings

[cjyuan]

Analysis looks good. Well done.

[gai93003]

Thank you.