Array Cast merch now available!

Pleased to see my favourite, the throw pillow.

@pamphlet Hi there. Interested in APL?

@xpqz Maybe we should have K, J, and BQN pillows in addition to the existing APL pillow, so we can have an array pillow fight?

@Adám one could arrange them in actual arrays on the sofa.

So meta.

Fridge magnet set with apl glyphs would be eh cool.

Not sure my wife would approve.

"Team ⎕IO←0"

Maybe a 'Strands' 'delenda' 'est'

@xpqz It would. Now I want to know if this actually arrives as 7 separate magnets. If so, then I can make a single image which becomes a bunch of separate glyph magnets.

I'm going to order a slate grey Array Cast dad hat, because why not.

Won't it be hard to read the black on slate grey?

From the product image it looks fine. But as it's a rendering, it's hard to say how it will come out on the physical object I guess.

I'm looking at custom die cut sheets like those used for words to create messages…

Shipping, ouch...

£30 > pain threshold for a hat for me.

@Adám lol

@xpqz lol xD

Join me in 15 minutes for a webinar on user-defined operators.

@Adám Thanks. Was a very usefull one! You were asking again for questions, but the chat function was closed.

@Adám Nice video! Question: at 15:20 you said "..tradfns and dfns. We are not going to deal with fully tacit functions and operators in this webinar". You seem to suggest that tacit operators can exist, but I thought operators CANNOT be defined tacitly

@Richard Oh, that's too bad. I think it is only open if you join after the stream starts. I'm happy to answer questions here or through comments on the video.

@pitr Dyalog currently only supports one type of fully tacit operator, namely a monadic operator derived from a dyadic operator with a right operand: ⋄ _Twice←⍣2 ⋄ 1+_Twice 10

@hyper-neutrino Where is the bot?

ah sorry, i had to force restart my server yesterday and forgot to turn it back on

Btw, can you give user16170614 access?

@Adám done

Thanks.

CMC: leetcode.com/contest/weekly-contest-291/problems/… efficiently

The appeal of a string is the number of distinct characters found in the string.

    For example, the appeal of "abbca" is 3 because it has 3 distinct characters: 'a', 'b', and 'c'.

Given a string s, return the total appeal of all of its substrings.

What is a substring?

contiguous + non empty

a couple of test cases: 'abbca' -> 28, 'a long string' -> 425

("non empty" is unnecessary, as they would have 0 appeal, and thus not contribute to the total)

true

So, you want more efficiency than ≢⍤∊⍳∘≢∪/¨⊂

yes

BQN, O(n^2)

I have a 27 char dfn which is O(n) I think

and i have a 47-char O(n) BQN one.. now to making it not insanely long

26 in BQN so far; O(n) as long as ⊐ (like APL (∪⍳⊢)) on the string is O(n).

i'm still at 41; probably some different algorithm

Yeah. Mine involves a lot of algebra-ish simplification.

22 with some golfing.

And 19 as a train.

nice

25 for a flat array version; really think it should be possible to shorten that.

Solutions

mine

Okay, figuring out why these are equivalent seems really painful.

@dzaima Got this down to 33.