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Agreed. This was one of the better challenges. Especially the fact, that most people (including me) ended up with the 'circle + garbage' images first :D

Without the 'US' hint, this one is really hard.
Of course there is the title, but still.

This one took waaaayy too long. I probably looked at the string 'ANSWER' for hours and couldn't find the final step. That last one is a bit random, for my taste.

This one took me a while. I always assumed it was some old-ish Layer-1 protocol, but somehow I never ended up at RS-232. Except for today.
Then it was just a matter of messing around for a bit. Does every letter have a Start-Stop envelop? Ahhhh, LSB first... And well, there it was.

Had the browser console running, got the X value from the request, pasted into a small tool I build which downloaded the JAR, unpacked, decompiled (thanks to jd-cli) and gave me the password back :D
No problem in under 20s^^ I want to see the 1s challenge ;D

This challenge took me about 15min .. A LOT of luck was involved, I guess. Decoding the 80s into numbers was straight forward. Looking at them (with 'world' in mind) they seemed like they could be coordinates. One of them starting out with 54 was even better, because Europe and such. Ended up in Rus...

No idea why there are 12 iterations ...

Got some sample data, ran into exceptions from the formulas pretty fast ... well.
Querried all the data over night (19MB JSON^^). Rendered all layers into their own image and wondering whether I would/could detect anything in there. Realized I overdid it a bit.

This one took quite a while, agreed. So realizing I'm looking at a (half)byte stream of a BMP file was the easy part. What helped A LOT was at least doing the header by hand, to get file dimensions and such. Shotcut produced 365.475 JPG files which matched the 5624 byte file size, given in the heade...

This took a few years ... but z390 was the ticket.

Okay, this one was fun and didn't take too long.
But switching to MD5 on a modern version ... that took a while to find out.

I just analysed it, too, reduced it to ((p in base 3) + (k in base 5)) from base 7 to base 10. Yup, that's pretty much what I did. Going through the code and having a good, long stare. Outcome was something like this: ... # main_1 60^<0^2? # push 6, duplicate, get mem[6], duplicate, jump 2 (to !) i...

Like I already hinted in the non-solver forum, I'm pretty impressed with the design of this challenge. I, like others, used a hashing scheme to identify the duplicate. Good old memory-time trade-off. Glad I remember some of those university lessons ;-D The author basically set up the test sets to me...

I'm currently working on this challenge and without spoiling too much, I've got to say that the test sets used to validate the code are very specific if not mean :D

I consider the task (or more the text) to be imcomplete.
The fact that there are only positive integers should be mentioned!

At first I looked at the SHVM documentation and instantly hated all of it. Put it away for a few years. Now, that I tried it, it's kinda fun. Definitely more than the HVM. I took a pretty straight forward approach to this one. But looking at the other solutions, I'm already learning. * first loop re...