What's the point of embedding the LCS problem in this dynamic-cast mystery problem?

All most all code examples in hackerrank C++ are

1. Lacking proper variable naming conventions.
2. Lacking proper const conrrectness and use of const refereces where ever possible.
3. careless use of copy and having too many memory leaks. 4.Lot of redundancy in problem information ex:- some problems give you length of string as input and then the string. why ? you can find the length directly from the string alone.

These do become important when you do real world programming for production quality code.

just FYI:-

Note: This is a very bad code example!

The code is producing memory leaks!!! none of the cast spells is ever deallocated in main. Do not do that! if you need a polymorphic return use std::shared_ptr and make_shared or unique_ptr and make_unique.

The great problem with this test is that the english words used are trick and cause difficults to non-english native speakers to understand.

I tried this out yesterday and can't seem to grok the criteria for:

"If it is a generic spell, find a subsequence of letters that are contained in both the spell name and your spell journal. Among all such subsequences, find and print the length of the longest one on a new line."

They're definitely not continued subsequences, and I thought it would be shared letters in order but that's not right, either.

Can anyone specify the constraint in a clear manner?