. means function composition in Haskell. (f .) . (+) is just an obscure way to write \x y -> f (x + y). It’s not recommended to use this point-free style in production code, but it is sometimes fun to experiment with for challenges like this.

They are considered volunteers in the Netherlands as long as the compensation is way below market rates. I don’t understand why you think this is a problem.

In the Netherlands, volunteers can be paid up to €5.60 per hour and up to €2100 per year (tax-free).

The Netherlands also has mandatory ID.

Not only is it convenient, it also enables parallelism:

“How to Think about Parallel Programming: Not!” - Guy L. Steele Jr. (Strange Loop 2010)

I’m confused. It does go straight to the discourse post when I click it.

You can choose a custom donation and make most of your money go to the EFF. Then the top tier is just like a €24 donation to the EFF and you only really “pay” €10.30 for the actual books.

Een belangrijke overweging van mij is dat de partij groot genoeg is om echt het verschil te maken. Daarom ben ik recent lid geworden van Groenlinks. Ik denk dat Groenlinks-PvdA de enige fractie is die groot genoeg en ook duidelijk pro-europa is.

Or anywhere in the EU. And I don’t think the USA is more lenient on piracy. But perhaps they are if a big company is the one doing it.

That’s is how things used to work here in the Netherlands, until the EU forced us to change our laws in 2014:

https://globalfreedomofexpression.columbia.edu/cases/aci-adam-bv-and-others-v-stichting-de-thuiskopie-stichting-onderhandelingen-thuiskopie-vergoeding/

Why? They immediately explain that the difference in performance would not be significant on such a small problem and I see no other reason to prefer arrays over maps.

Thanks, I did look at the Wikipedia page, but the Applications section is pretty difficult to read. The applications it lists are themselves quite abstract problems.

Also, I think the ‘find’ operation could be replaced by an operation that checks if two elements are in the same set. That way you don’t have to come up with a “name”.

One thing I’m missing is which problems this technique can solve. I believe one important use case is in type inference. Are there many other problems that can be solved by union-find?