[mervereis]

Learners, PR Template

Self checklist

• 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
• My changes follow the style guide

Task code

CYF-1183

Changelist

[cjyuan]

Code looks good.

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

[mervereis]

Code looks good.

Could you use complexity to explain how the new implementation is better than the original implementation?
@cjyuan
The original implementation has a time complexity of O(n²) because it loops through every character and uses not in s to search the entire string each time.
The improved implementation has a time complexity of O(n) because it creates a set of unique letters first. Checking whether a letter exists in a set takes O(1) on average, so we avoid repeatedly searching the whole string.
Both implementations use O(1) extra space for English letters, because there are only 52 possible uppercase and lowercase letters.
Overall, the new implementation is more efficient, especially for very long strings, because it reduces the time complexity from O(n²) to O(n).

[cjyuan]

What about the complexity of original and the improved find_longest_common_prefix?

[mervereis]

What about the complexity of original and the improved find_longest_common_prefix?
The original implementation has a time complexity of O(n² × m) because it uses nested loops to compare every possible pair of strings. Each comparison can take up to O(m) time.

The improved implementation has a time complexity of O(n log n × m) because it sorts the strings first and then compares only neighbouring strings.

Both implementations use O(n + m) extra space.

Overall, the improved implementation is more efficient because it reduces the number of string comparisons, especially when working with large lists of @cjyuan

[cjyuan]

All good.