HOMEWORK 9: Tiktok Trends


NAME:  Jinshan Zhou


COLLABORATORS AND OTHER RESOURCES:
List the names of everyone you talked to about this assignment
(classmates, TAs, ALAC tutors, upperclassmen, students/instructor via
LMS, etc.), and all of the resources (books, online reference
material, etc.) you consulted in completing this assignment.

A lot, like using Top K for better sorting. Difference IO cases (not useful).
StringCache (not useful). shared_ptr (not really help) and may websites, cases
that I don't remember anymore.

Remember: Your implementation for this assignment must be done on your
own, as described in "Academic Integrity for Homework" handout.


ESTIMATE OF # OF HOURS SPENT ON THIS ASSIGNMENT:  over 20 hr, 8 hr for complete
more than 10 hr just for optimization.


MISC. COMMENTS TO GRADER:
The program is a bit messy. Since, I tried too many techniques. Some are broken
changes, so I have to add patch to it. Myself is also a bit lose to my code.

## Reflection and Self Assessment

Discuss the issues you encountered during development and testing. What
problems did you have? What did you have to research and learn on your
own? What kinds of errors did you get? How did you fix them?

What parts of the assignment did you find challenging? Is there anything that
finally "clicked" for you in the process of working on this assignment? How well
did the development and testing process go for you?

This was definitely the most challenging assignment I've ever seen, and the
hard part was identifying performance issues and optimizing them. It was not
easy, I used various tools like perf and found that the JSON part had the biggest
overhead. Optimizing it showed immediate results, but then I hit a bottleneck,
so I started using various schemes, and most of them didn't work. Then I had to
push back and design the business process from scratch and finally got inspired
by my professor to use unordered set to get the best performance
(last 0.1 seconds).