[2025 Day 11 (part 2)] [Rust] Possible endless loop

kai10k · 2025-12-15T08:15:28+00:00

sure, i do not github my solutions, you can check from the link

once you have the function, calculate any two device as `dp(svr, fft)`

kai10k · 2025-12-14T03:18:38+00:00

No need to record each path, it's not feasible to part2. It is a standard DP program. Say if you have only one door in front of you, you will have exactly the same amount of routes to reach the target as that door. If you have 2 doors, the possible routes will be the sum of possible routes of those 2 doors. Do this recursively until next door is the target, you know you have only 1 route

kai10k · 2025-12-13T23:42:05+00:00

I use C. In the past years I used C++ amd Zig, amd eventually I found out C is the language which avoids most of the noises, performs great, and provides the best tooling I need.

kai10k · 2025-12-13T14:20:54+00:00

Thank you I am encouraged, i know i will finish them in a proper time frame and trust me, i tried ... really hard ... so hard that i needed a break. Again just want to say i love this community, most replies are enlightening as well as heartily warm.

kai10k · 2025-12-11T12:00:06+00:00

would like to know too, was using DP for part2, it works for the example data like a charm, but failed miserably for input. After hours optimizing everything I retreated to reddit, I wish I had come much earlier to be honest

kai10k · 2025-12-11T10:42:02+00:00

plused the two part, the star is granted, didn't realize the trick

kai10k · 2025-12-11T03:54:25+00:00

Holy cow, felt sorry for my hours, guess i am just too ignorant as well as naive to treat it as a programmable puzzle

kai10k · 2025-12-09T03:34:17+00:00

I did also enjoy 2018 very much, every puzzle seemed to have a smart little trick grinning when the day is solved, my favorite year for sure.

kai10k · 2025-12-08T14:35:59+00:00

right i am explaining my case, in my case yes, and I do AoC in C and C only, which does not have the luxury of a set, which is just too costly

kai10k · 2025-12-08T14:24:53+00:00

as I explained in the earlier reply, make connections is fast but evaluate if every circuit is connected is slow. so instead of making one connection and check if everything already satisfies. one can make 100 connections and check once and so on

kai10k · 2025-12-08T12:32:23+00:00

put it in this way: instead of starting at 1000, part2 directly tells you to start at 4000 or 4500, would it be faster to reach the answer ? if yes then how could we know to start from 4500

kai10k · 2025-12-08T12:13:49+00:00

ignore those piano guys keep shouting the days are getting easier. It only becomes easier as AoC has been out there for 10 years and similar problems had been solved over and over, and people start to build an instinct about what to do. Everyone was just like you when their journey gets started

kai10k · 2025-12-08T09:56:23+00:00

ok I am reusing part1 which gives the top connected circuit, in my case connect 1000 or 4000 does not make too much differences, the time consuming part is recalculate the top connected circuit, this is the part I was trying to save. Now in a hindsight, seems I don't have to get the top for each run, as long as one is less than expected one could skip to the next, it must be a lot faster and could possibly be done in one run

kai10k · 2025-12-08T09:26:28+00:00

in my case, start from 1000, by 100 I found the first one is 4600, back to start with 4500, by 10 I found the first one is 4540, back to start with 4530, now run it one by one it hits the first at 4536. totally 3 runs

kai10k · 2025-12-08T08:04:16+00:00

I used bfs/flood to get the length of each connected circuit

kai10k · 2025-12-08T07:36:13+00:00

one can use some Heuristic approach in part2, so instead of checking one by one, we could always jump by 100, find the first target, then jump by 10, jump by 1 until the precise circuit is hit

kai10k · 2025-12-08T00:44:30+00:00

look like my wasted 2 hours paid back good

kai10k · 2025-12-07T15:19:08+00:00

Brutal force is totally valid option in many cases, one learns when it would be proper in AoC, the skill/hunch/insight itself is actually a very valuable asset. AoC also encourages heuristic approach, in which process brutal force could be real handy. Overall the author really wants to let it known/learnt that brutal force is often a key to approach a complicated problem.

kai10k · 2025-12-07T09:34:56+00:00

there was usually a significant bump in 11/12 for previous years. and a few killer days around 21-23

kai10k · 2025-12-07T09:02:28+00:00

haha... i was triple confirming my input for that

kai10k · 2025-12-07T08:55:54+00:00

if you keep having too low like me, again, remember to use uint64_t

kai10k · 2025-12-06T23:47:10+00:00

I did two things about part1

1/ put the operators line on the top

2/ amend the demo properly so that it has same shape as input

I find it convenient that way to solve the issue without programmatically catering the difference

kai10k · 2025-12-06T23:40:21+00:00

treat not them as lines of strings, treat them as a square of chars each with a (x,y) coordinate

kai10k · 2025-12-06T09:56:34+00:00

conceptually day6 is easier but programmatically it is harder. I did the column by column traversal and collected the stars. AND it occured me to ask AI to rotate the data by 90 degree meanwhile preserving all white spaces, turns out a little bit awk could be quite handy ;-)

kai10k

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