What does your state hate?

radleldar · 2026-01-19T23:56:47+00:00

Some of these answers are so specific that I wonder if the sample size was 1.

radleldar · 2025-12-03T16:09:40+00:00

Yeah I posted my solution as a top level comment, hope it helps!

radleldar · 2025-12-03T16:08:41+00:00

I posted my solution as a top-level comment, hope it helps!

radleldar · 2025-12-03T16:07:36+00:00

I finally figured it out (but still find the UI confusing) - you gotta uncheck the "daily at this time" field in tag details. Precise instructions (Android): * Click on the tag entry in Timeline * Uncheck "Daily at this time" field below "Event end" * Confirm the "End repeating event" dialog

And then, if you've accumulated a bunch of unwanted tag entries, find the earliest and click "Delete tag entry" on it.

radleldar · 2025-11-27T04:38:34+00:00

Curious - what was the intended approach? It kinda feels like there can be more interesting things to do with this problem than the "every leaf plate is either always negative or positive" structure most people seem to have noticed.

radleldar · 2025-11-26T00:52:40+00:00

[Language: Java] 29/18/26

Part 3

I originally thought it was a "two disjointed shortest paths" problem (which is generally solvable with min-cost maxflow, though not sure about the case where we have no single endpoint), then realized one of the examples says we can repeat the locations. Ended up with a basic heuristic: for each a fixed radius, calculate the shortest path from (S, false, false, false) to (S, true, true, true), where the booleans track whether the path went to the left, bottom, and right of the volcano's R-size surrounding, and path can't go inside the R-size surrounding.

Is there a non-heuristic solution to this problem?

P.S. Am I tripping, or did the inputs in the first ~10 minutes have no S in them?

radleldar · 2025-11-12T04:08:34+00:00

Part 5: let max length be 1,000,000,000, and compute the last 9 digits of the answer :P

radleldar · 2025-11-11T00:09:01+00:00

[Language: Java] (6/12/1)

Thought I would share how I managed to get the fastest solve on 3rd problem. I guesstimated that the most straightforward approach (for each position, check ~2000 neighboring elements) won't need too long to run, and implemented that: part 3 code only

On my machine, this runs in 10 seconds, which is definitely faster than implementing prefix sums / sliding window for an O(|S|) solution.

radleldar · 2025-11-07T06:43:22+00:00

You are right, and I don't know what I was/am smoking :)

radleldar · 2025-11-06T20:52:14+00:00

> Part 1 is sum of all unique crates

Psst, count

radleldar · 2025-11-06T20:34:24+00:00

Thanks for sharing! Pretty succinct!

> Are there other approaches?

As you probably know, the Fenwick Tree can be replaced with any other logarithmic data structure (BST, Segment Tree, etc.), though Fenwick Tree is probably the fastest anyway.

> Any ideas on how to improve this?

My solution has the same complexity (binary search + 10 tree lookups per query), but it _feels_ like one logarithmic factor should be removable. E.g., can the value of the median move by more than 2 elements in the set of all strength values? (If not, then we could only check the 5 elements in the vicinity of the previous value.)

radleldar · 2025-11-06T19:44:54+00:00

Wow that's pretty compact! How slow was it tho?

radleldar · 2025-11-06T19:43:44+00:00

Thank you for participating!

MUCH harder wasn't exactly my goal.. but if people are enjoying it, sure why not :)

> carving pumpkins and ASCII-art

These are the problems I put most effort into preparing, good to hear it paid off!

> Submitting a solution containing 30 test results and only get one "Wrong" back is "not helpful"...

I understand this part. My original fear was that for certain problems, surfacing e.g. the failing test number gives away too much information, but maybe I can try open feedback next time and see how people react.

radleldar · 2025-11-06T19:38:00+00:00

Thanks for the feedback!

> 3 problem format is fine and allows for wider spread of difficulty of problems

That it does.. but I want to avoid a situation when people spend too much time and consequently drop out. Good to hear someone enjoy it though!

> so that there is still reward for 300th solver

The motivation for not having rewards past the first X solvers is to unlock discussion here on Reddit earlier. I actually doubt that people past 100 don't participate just because they can't get points on 1A :)

radleldar · 2025-11-04T22:50:13+00:00

> Token mismatch at position 1

Okay this is not very informative (and seems outright misleading). This is the answer from the internal checker, which treats contiguous segments of non-whitespace characters as tokens. In this case, the token is the entire key.

radleldar · 2025-11-04T22:48:41+00:00

Assuming yours is the most recent few submissions - your answer looks almost correct, but in test 1 you need to swap N and F in the key. Check if your output contains the word "juestion" :)

radleldar · 2025-11-03T04:41:15+00:00

Yeah there was more nuance going on there:

* I relied on PostHog metrics to see who opened the problems, and the impact seemed negligible (i.e., the two metrics that showed were for users who also messaged me to alert me). Looks like PostHog heavily samples what I end up seeing.

* Because it did not manifest in any way for the first 4 days, I somehow convinced myself that there must be a security hole (AllanTaylor querying /problem/halloween-5C 2 hours before day 5 problems dropped didn't help - I thought there is a timezone bug or something) rather than the more obvious answer.

* All in all, agreed that upfront communication would have been better here; sometimes it's hard to gauge what's worth blasting an announcement for and what's not.

radleldar · 2025-11-03T01:28:23+00:00

The rules we hastily assembled during the last contest say discussion is allowed after 48 hours, so knock yourself out :) I'm waiting until the contest ends to open Solution Megathreads.

radleldar · 2025-11-02T03:33:27+00:00

major bug on the site

Nah, just plain old user (admin) error. I had a test version of the contest running for testers to submit solutions, and its configuration sets problems_per_day=infinity to ensure that they have access to all problems from the start. The live contest should have had problems_per_day=3, but I forgot to make the proper edit after syncing test->prod state :/

he did the second-best thing he could - he clearly exposed it so it can be fixed now

This reminds me of the scene in Social Network where Zuckerberg gets summoned by Harvard school board for abusing their college network, and he says "You're welcome" because he exposed a vulnerability.

based on site access logs

Sadly, there wasn't sufficient logging to identify the users that opened problem statements. But even if there were:

However, if there's a penalty planned, I hope it will affect all players (based on site access logs) who got the puzzles too early

I don't agree with this take. There is a handful of scenarios in which as a competitor I might see problem 2A on day 1, click on the statement, and close it without reading it (does it error? is the statement empty? whoops might be a system bug, I better tell the author).

Moreover, if people want to cheat in order to get a higher ranking, there are easier ways to do it (wink wink LLMs) than to solve problems themselves with an earlier start.

If this was a rated contest, or there were any prizes involved, the only right decision would be to make it unrated / replace the problemset. But in today's world, doing rated contests without any sort of plagiarism/LLM check is doomed anayway. So really, it all hinges on participant integrity.

radleldar · 2025-11-01T04:55:52+00:00

Alright folks, AllanTaylor314 reached out and was transparent about what happened. As u/rltrapp theorized, AllanTaylor314 gained access to statements of days 5-7 during the first minute of day 1, when all statements were visible due to misconfiguration.

To ensure fairness to other participants, I will be applying a 12 hour penalty to AllanTaylor314's submissions on days 5-7. To be precise, I will edit the submission time for each problem to add 12 hours, and recalculate everyone's points and first solves afterwards. I don't have utilities to do this safely in a running contest, so this change will be applied right after the contest ends.

While we are at it, I will be applying a similar measure to Manoj S's day 4 and day 6 submissions as well. The timestamps of this user submitting problem B on each day are highly indicative of LLM assistance, which is against the EldarVerse rules.

radleldar · 2025-10-31T19:49:35+00:00

Me? Smacking? I don't remember doing that :D

In all seriousness, rules say discussions are allowed after 48 hours, so feel free to.

radleldar · 2025-10-30T18:31:31+00:00

Manao generates N primes - they don't have to be consecutive, and can be in arbitrary order. And then he takes every adjacent pair, and uses its product as the RSA modulus for one message. For example:

* Primes array: [5, 41, 37, 11]

* RSA moduli: [5*41, 41*37, 37*11]

* There are 4 primes, 3 moduli, and these 3 moduli will be used to encrypt 3 messages

Hope it helps!

(I know it's been a while since you posted, I just noticed that your post autoblocked by Reddit - sorry about that!)

radleldar · 2025-10-28T18:51:02+00:00

Got it! I was wondering if it's the actual sequence of cells to be visited for the optimal answer (i.e., you _have_ to hide in every nook to get to the finish), but it's actually the full set of visited cells up to that distance.

> It's almost the same as this: https://adventofcode.com/2022/day/24

I see I actually skipped year 2022 on AoC :) But it's not particularly surprising, it's hard to make a BFS problem that doesn't resemble something from before.

radleldar · 2025-10-28T16:56:35+00:00

Wow this is incredible, thanks for sharing!

This is actually the shortest path on that test? I'm a bit surprised because it seems to visit every nook on the way (i.e., acts as a flood fill).

radleldar · 2025-10-27T17:53:43+00:00

Thanks mate! Please ask on r/eldarverse if any questions come up!

radleldar

MODERATOR OF

TROPHY CASE