I couldn't pass the test so I unlocked and tried the solutions. To confirm newmaidumosa's guess, all of the 14 solutions now time out and no longer pass.

For begin: 20, end: 39, step: 5 you'll have: [20,25,30,35] to calculate the sum.

The last element is meant to be 40 if your upper limit is 40, but the sequence ends at 39, so you can only reach up to 35 which is the previous element of 40.

The comprehensiveness of the sample tests in Haskell is impressive. Thanks!

I'm not able to see the test cases either, but I guess it could be the case of "a plateau at the end of the array" other comments are talking about, for example:

[1,2,3,1,2,2,2] shoule return PickedPeaks {pos = [2], peaks = [3]}.

Thanks for the nice kata! Also I'm the 1000th to complete it, screenshotted to celebrate ^_^

The Ctrl+n Emacs keybinding (next line) doesn't work for me (Firefox, Linix), it opens a new window as is defaulted by the browser.

Is the next line function reassigned to another binding, or should I try to override the browser's default behavior? Thanks!

If you are stuck and wanting to unlock the solutions like me (in Haskell), try iterating over the input string fewer times. Good luck!

I need to learn to use zipWith and remember that maximum is in Prelude.

The (Money, Int) tuple is redundant, refactored to just count the number of 25 and 50 notes.

Haskell random test might be generating some weird Chars, I could not figure it out myself.

TIL spoiler comments are also hidden from the commentor who has not solved the kata.

It pushes me to read again the error messages to find out that, as mentioned below, the key is that f always has type Int -> Integer.

Turns out I wouldn't have learned that there is upper camel case (HelloWorld) besides lower camel case (helloWorld) if not for this kata.

Link to the wikipedia page: https://en.wikipedia.org/wiki/Camel_case