This challenge hub contains an answer-oriented recreation of some of the AquaQ Friday Challenges.
The challenges were designed to puzzle someone using KDB+, but since an answer is all that is required, they are now language agnostic. Answer as many as you can, collect a few badges, and if you like, show off on the leaderboard (though keep in mind you won't show up until you've completed at least one challenge!). No record is kept of attempts beyond the time of your last one, nor are wrong answers kept.
Rate the challenge difficulty as you complete them, or as you work on them - you don't have to finish one to rate it!
An API is available for the leaderboard. The board json contains the challenges completed by each user on the leaderboard, and the badge json contains a list of their badges. Please approach this sensibly - the board is unlikely to change on a minute-to-minute basis, so try to keep queries at intervals of 5 minutes or more.
Sometimes it might seem like you can't get the right answer:
Re-read the puzzle carefully and check that you're following all the steps.
Check that you're inputting the answer in the correct format required by the question.
Double check your input - have you lost any of it somehow?
Check your counts, indices etc - off-by-one errors can be frustrating.
If you've tried all of the above but think there is a flaw in the question, email me. There might actually be a mistake!