Thoughts on Puzzle 19 : Wild Thermometers

I just found out I’m not eligible to compete in my country.
OOPS
Smart for the puzzles, not smart to read a disclaimer.
Double check everything people. :rofl:
Whatevs, it’s been fun. My brain needed a stretch.
The best of luck to those eligible.
I’m out.

I am from India, and that’s the first thing I do when I start with any online competition, as I have seen many a time that India is never on the list of eligible countries. But for this, it is.

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Probably only @Drew or @Community_Team or anyone else on the team can answer that.

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I am not worthy! Spent 6 hours and its now 3 am. Maybe I’ll try again in the morning. But for now, I give up.

I do this too since I live in India as well.

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Its called Capacity/Cardinality/Exact constrain
It can be complex but sat solvers has it out of the box
for example using: ISolver (SAT4J core 2.3.1 API)
constrain for the first row:
solver.addExactly(new VecInt(new int{1,2,3,4,5,6,7,8,9,10,11,12}, 6);

Hey @popopo_champ Italy is eligible for our hackathons. I will make a note and send you a link when the next one goes live (next week sometimes) for pre-registration. Each country has its own rules and regulations around sweepstakes and drawings. In terms of this puzzle sweepstake, each country also has a cost for legal to get approved to run an event like Hack the Galaxy. Some countries are easier than others and that is all I know about it really. We worked with legal teams for months to target geos and get as much of Europe eligible as we could. We just finished a hackathon on Virtual Accounts and Wallets – you can see projects here. So there are other ways to win prizes. We offer cash prizes to our hackathon winners as well. Good luck and I will be sending you a direct message later today. Best, @Drew

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Wow, didn’t know there’s a lot of process in order to legally run sweepstakes in a country. Out of curiosity, I searched and read about the rules and regulations that are in place for sweepstakes to be held in India. I read some rules for that of Italy’s as well, and I can see why it would be tough to check all of them.
I appreciate the Rapyd team’s efforts in order to run this competition in countries other than in US knowing that it’s not a straightforward or simple process to do that.

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Great tip!

I could solve the first Thermometers puzzle (in set 1) easily by hand, but this one resisted me; I was stuck with having to try out guesses and backtrack, which I hate doing by hand.

So I had begun writing a program for it, looking for ways to implement the constraints.
This tip on using a SAT Solver made it for me. Thank you!

144 boolean variables and 3 sets of constraints:

  • Constraints for row sum
  • Constraints for column sum
  • Constraints for thermometers filling

Feed it to the SAT Solver and boom! there is your answer.

Going by many comments on this topic, some are talking about guesses and backtracks when doing it manually. I thought there was no way other than that. But when I started solving this, I did them without doing guesses. There is a simple step-by-step process to come to the conclusion of which cells will be filled and which cells won’t be filled.

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I finally got it and people who are stuck on it the way I got the answer was I simply just went for it without any thinking it took 2 days and a bunch of scrap paper but one day I decided I was just not gonna give to much thought about it and i just went straight for it so for the people who are stuck just don’t think about it to hard just start from the begining and just go for it and you may have to fix a few mistakes but eventually everything will add up

I started on puzzle 17 and beat it pretty easy and 18 beat it pretty easy to this one was challenging for me but in the end I finally got it and was soo happyyyy

Probably something about taxes.
But, I remember that, legally, if the prize is money and it’s sent as donation it isn’t a problem and it’s not taxed.

omg my brain is literally on fire. im glad i did this one was hard af

This one was great!! I solved using paint and filling the grids with two colors. I’m trying to learn C# rn and I’m very interested how can you do this puzzle with coding. Anyone who did that maybe want to tell us their steps or just give a few clues? It would be amazing.

Yeah, I also want to know the code for this puzzle. Now, since this puzzle is expired.

Yeah, I read a clause that was something like that. It simply says that if the winner doesn’t accept the prize, the same has to be donated to a non-profit organization.

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Do you have tips on steps to use without guessing where things go?

Ok, you can start with the rows and columns with the smallest sum of filled spaces, which is 1 in this case.
Observe the row with 1 on the left, there are three thermometers in that row which has more than 1 space within that same row. Those are (delta), (gamma) and (epsilon), and only the bulb part of those thermometers can possibly be filled. So you can mark the remaining parts of those three thermometers as red or ‘0’. This way you remove the cells which will never be filled.
Similarly do the same for the column with 1 on the top, you can see towards the bottom of that column, only one thermometer (gamma) that came from a nearby column and it has more than 1 cell within that column. You can mark the tail part of that thermometer as red or ‘0’.

Do the same for the rows with 3 as the sum.

Mark green or ‘1’ where you know a cell of a thermometer will definitely be filled. And hence, starting from that point to the bulb will definitely be filled.

Then the cells where a thermometer has bent are also crucial. By using the above strategy, you can determine which part of a bent thermometer will be filled or unfilled.

This way, gradually you will progress towards the solution.

I solved this with LPSolve IDE which is an open source program for solving integer linear programming problems.
lp_solve reference guide (5.5.2.11) (sourceforge.net)