Because only rows 1 & 2 are reported. Row 0 becomes [0,0,0] after 'S', and the instructions state that the smallest possible array is reported where any row or col has any element > 0.

I did the same thing! I wrote out my solution assuming that punctuation would be part of the word (like in "Hi!"), then got error messages about punctuation. I also left it in, just because.

Thank you Geoff for replying, I am currently thinking about ways to achieve that.

After a bit of reading my solution is probably O(n^3), way off the mark! I'm having trouble imagining another solution that doesn't get into more loops to perform some sort of look-around (effectively my original solution). Memoization seems a bit of a stretch also (but I may be wrong).

You don't need a sieve to calculate prime factors. Its OP. Look at trial division.

Yes, I'm aware of that one as well. @functools.cache is a newer version of lru_cache and supposed to be faster, but is > 3.9 only.

Turns out memoization wasn't the solution to my problem anyway.

you're looking for functools.lru_cache

Oh! My bad, it's a 3.9 addition. I'd read the docs wrongly. Apologies.

Are the newer Python 3.8 decorators supported? I'm trying to use @functools.cache and receiving an error after functools is imported. This works fine locally on my machine. I want to use this to memoize my functions as I'm currently hitting the execution timeout on the full test suite.

Traceback (most recent call last):
  File "tests.py", line 1, in <module>
    from solution import *
  File "/workspace/default/solution.py", line 3, in <module>
    class DirectUnweightedGraph:
  File "/workspace/default/solution.py", line 37, in DirectUnweightedGraph
    @functools.cache
AttributeError: module 'functools' has no attribute 'cache'

Chrono79, thanks. btw, sorry for flagging it as an issue instead of a question. First discourse post, etc. etc.

Damn thats cool as fk, I guess you learn somethign everyday