Fully agree on the input mutation part.

Wrt variable name l: you just need an appropriate font ( like the one used here ). Also, i and j are perfectly descriptive for a counter, and l is arguably perfectly descriptive for a length. I have more problems with not using pyramid[][] +=; even switching the arguments to + ( and adding a couple extra spaces ) would have been better.

Which language does not have that example test already?

This should absolutely not be happening; pyramids are fully intended to be triangular from 1.

Please state the language that has this problem ( test suites are different per language ), and ( where applicable ) make sure you are not mutating the input; this can lead to unexpected results.

( If your language is JS, which it seems to be, I really don't see how this is possible with the current test suite, even when mutating inputs. )

a subsequence is not necessarily an infix. tests should have caught this.

Not gonna happen anymore.

It's a 4kyu kata and it has an appropriate tag. I'm conflicted. How much do you want to spell out brute force won't cut it?

Ask in Discord#reviewing. There is someone who speaks Lua there.

Yes.

Look at the tags,

Look at the tags

JS has random tests