That explains it, thanks. Amusingly the wikipedia "longest common subsequence" page emphasises that this is different to and commonly confused with the "longest common substring". Illustrating this confusion neatly, the OP's repository implements subsequence, but is not only called substring but documented by a wikipedia link to substring!
Does anyone actually ask this sort of thing in an interview anymore? (I don't mean this as a knock on the repository, which looks very nice aside from the lack of tests.)
I recently interviewed with an SF consulting company (a sort of network/placement firm), which purports to offer only the most senior devs to the hottest companies. The process includes a timed puzzle-solving test.
Ironically, fresh CS grads are more likely to do better on such a test because senior devs have filled their minds with ways of solving real problems and building complex living systems that actual humans use. They know that the once or twice a year they need to solve such a problem, they will likely find it well-solved in a library or site like this one. If not, they know that the boss will not be holding a stop watch over them -- she measures productivity in person-months, not person-minutes.
Even more ironically, this particular test also rewards premature optimization by stress testing your solutions for micro-optimization.
Yup. I just did an interview that was hours of this at one of the larger California companies.
The only way to ace is to memorize the implementations otherwise there was no way to get it done on a whiteboard in 20 minutes.
There were a lot of added weird constraints as well like implementing sorts with singly linked lists in constant space (not lg(n)) preventing the use of recursion or a stack in order to make a simple implementation.
I would say that the entire interview was basically a test of your knowledge of the companies published information as well as the algorithms linked to in the prep email sent by the recruiter.
Pretty much zero interest in the knowledge and skills you do have. Only one interviewer out of six asked questions about the resume and even then only briefly.
Might I humbly suggest that you check out some videos of the algo you're trying to implement on YouTube first and then try implementing it w/o looking at (pseudo)code. I gave up my first 2 times and peeked at code, but after those I got the hang of it. Also tuples.
https://github.com/kennyledet/Algorithm-Implementations
A fellow by handle of Yonaba implemented many of them in Lua. And Lua looks basically like a (Pascal-ish?) pseudo code.