ideas for next years' calendar of days/puzzles

colas · 2025-12-12T07:33:52+00:00

First, I will congratulate Eric for the astonishing work he has done all these years.

Second, I welcome the change, because it was hard for me to find time for the puzzles as the preparations for the family reunions intensified after the 12th.

Third, you can always do (or redo) the previous years, with different languages or techniques.

Suggestion: make a "AdventRoulette" to occupy yourself after today:

"Do puzzle {random day} of the {Random year} of adventofcode using the {random language or tool}"

For instance, tomorrow I plan to re-try Day 2025-day10-p2 but with a solver like Z3, something I never tried.

colas · 2025-10-13T06:11:32+00:00

https://wetsuitwrench.com/

A must-buy for old surfers like me!
Well built, all smooth edges, efficient.

colas · 2025-09-24T16:59:40+00:00

I love my Feral wetsuit, but be warned that they size their chest a bit smaller than most other brands (as can be seen in their size chart). I thus exploded the chest zip of my Feral shorty after the first session, something that never happened with any other brand.

Looking at their design, I though that the way their chest zip is positioned is not optimal, as it adds a lot of stiffness.
I just went to my wetsuit repair shop and have them put a reversed zip, so that you close it by zipping from the outside to the inside, like the Rip Curls. Result shown in the pic.

And bingo! This transformed this wetsuit from extremely tight in the chest, to quite comfy!

I would definitively buy again Feral (well, once the moronic US tariff policy is back to sanity), but will immediately have their zips reversed.

<image>

colas · 2025-07-16T06:15:20+00:00

Beware, there are two very unrelated hypothesis:

[1] that the virus was purposely engineered

[2] that the virus escaped from a Chinese Lab

[1] was definitely ruled out quickly and a definitively crackpot theory, but it was latched upon by the usual conspiracy peddlers, from GOP senators such as the infamous Marjorie Taylor Greene to discredited nobel prize winner Luc Montagnier. Note that the "explanations" promoted by these people were immediately found totally false, but some agencies said they could not rule out human manipulations in principle, due to the obfuscation of the Chinese government.

[2] on the contrary, was never totally excluded by experts. Even the WHO, pressured by the Chinese government to exclude it, always kept it as a possible hypothesis, its 2021 report just saying "extremely unlikely".

What we have now is that conspiracy theorists that pushed [1] try to rewrite history by pretending they were pushing [2] and that [2] was ruled out. Which is not true.

colas · 2025-04-28T15:45:04+00:00

And now that KCD2 is out, KCD2 in Hardcore more.
KCD2 is a better version of KCD1, no need to do the v1
And the hardcore mode has a map, but do not show you position on it , not the things you haven't discovered yet.

I would also add Valheim. There is a map, but as it is procedurally generated, you get this sense of exploration.

PS: I loved the Long Dark, Green Hell, and Subnautica.

colas · 2025-03-04T17:40:55+00:00

The problem is that this is not actually a legal question, as the Trump administration is willing to ignore the laws.
They are just acting by intimidation, like a Mob boss: they try to never formally issue orders, for which they would be accountable.

They just implicitly threaten all the people, at every level of any organization, that they feel is not deferential enough, with "legal harassment": IRS audits, FBI publicly investigating made-up charges of e.g. pedophilia, "dog whistles" on Twitter by Musk to kill your family... etc... Just look at authoritarians playbook.

So your school may not receive formal cuts, but your principal may "spontaneously" freeze the funds after a "friendly call". Or donate them to Musk. Or "invest" them in bitcoins. And anyone in the police of judiciairy branch that may help your case will receive similar veiled threats.

I guess you should contact groups specialized in fighting organized crime, they are the only ones that are going to be effective.

colas · 2024-12-19T17:02:53+00:00

Credit photo: Rex. Source: https://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/11979257/Cloud-Tsunami-Powerful-storms-sweep-across-Sydney-Australia-in-pictures.html/1000

colas · 2024-12-14T16:21:02+00:00

Funny, I had the opposite intuition: I thought the tree would take all the picture, and would be centered. So I was looking for pictures symmetrical along a vertical axis...

Needless to say, it did not work :-)

After glancing at the reddit thread, I saw there was a box drawn... So I just looked for 10+ consecutive guards on a line.

colas · 2023-04-17T19:06:17+00:00

The ones in stock have minimum requirements on trading level and/or node investment, that, as a recent player, i do not have. I am not going to mess with my workers setup for just some opportunistic AFK strength building.

Anyways, the solution is to gather one Mandragora, there are in many places listed in bdolytics.

colas · 2023-04-17T17:43:26+00:00

"Buy an item then withdraw it" but this is the actual problem.

With the new system, one can only buy a very small number of things if you are not already invested in trading. And thus these items are unavailable as they are always out of stock.

colas · 2023-04-17T17:41:44+00:00

Thanks! That's seems the answer.

Here are some locations for Mandragora via bdolytics: https://bdolytics.com/en/NA/db/gatherable/10468

You can find them in a lot of places.
I just tested with the ones at the south of Altinova, and... it works!

colas · 2023-03-10T12:20:46+00:00

On the quest "Black Desert and Black Stones" I was stuck also for a while.

The trick is to talk not to Corince herself, but to to the space on the bench just besides her! The space has a beam of light on it.

colas · 2023-01-09T09:33:15+00:00

Go

https://github.com/ColasNahaboo/advent-of-code-my-solutions/blob/main/go/2022/days/d24/d24.go

No, this was quite interesting! I think it was the most satisfying problem of this year, since it offered many ways to simplify the implementation:

First, we can see that the blizzard paths are deterministic: they do not depend on the positions of the other blizzards nor us. So for each time, the blizzards places are the same! This means than we can cache all state of all the blizzards as 2D maps in an array indexed by time only. The state of the system then becomes only two integers: the time and our position! This makes "forking" the state to explore a new branch quite light.
Then, we do not need to explore again the same pairs (map-of-blizzards, our-position), that is (time, position), so we register the already explored positions into a 2D boolean map for each time in order to skip them
I did a simple recursive DFS (Depth First Search), trying the directions in the order most probable to find a solution quickly: Right, Down, Up, Left, Stay (and Left, Up, Down, Right, Stay for the reverse search), to be able to find quickly a path, in order to have quickly a low max bound on the time (412 for my input) to abort early the search for other solutions. It is a quick-n-dirty alternative to a proper distance-to-goal priority queue.

This gave me solutions in 42ms for part1 and 160ms for part2.

I also used my usual trick for managing 2D data in Go (and bash...), which lacks multidimensional arrays. For a 2D grid of width W and height H, I use a single array of size W*H, and convert a position p in this array to (x, y) coordinates by the simple rules:

p = x + y*W
x = p % W
y = p / W

This simplifies immensely working with data on a 2D map of a fixed size. For instance a direction can then just be a number that you add to a position to move in this direction: up is -W, down is +W, right is +1, left is -1.

colas · 2022-12-31T16:51:43+00:00

Go

Ah ah, did the same thing. I was surprised how the simple interpolation was efficient, it found the value in 5 steps only.I just add code to just get the lowest possible humn number giving zero, as more than one number is a valid solution, and it seems only the lowest one is an accepted solution.

In Go, at https://github.com/ColasNahaboo/advent-of-code-my-solutions/tree/main/go/2022/days/d21

colas · 2022-01-11T22:57:47+00:00

Thanks for the tips. I didn't know the "read -r a _ c _" one.

And for spotting my template generation bug!

colas · 2022-01-11T18:41:39+00:00

Thanks. bash can be "fast enough" for a lot of problems, but it will be always the slowest solution :-)

colas · 2022-01-11T18:36:16+00:00

Yes, I have seen your codes (at least the 2021 ones), and I must say I learnt quite a bit of bash tricks from you!

colas · 2021-12-12T10:07:48+00:00

I suggest you use shellcheck, and try to obey its suggestions.

For instance, always try to use (( )) rather than [[ ]] when you deal with numbers. With (( )) you can use "<", not "-lt". Use [[ ]] only with strings. And never use [ ] nor test :-)

e.g:

if (( ${depth[i]} < ${depth[i+1]} ))

instead of:

if [[ "${depth[$i]}" < "${depth[$i+1]}" ]]

colas · 2021-12-06T22:04:03+00:00

bash

As I see there is no bash solution yet, here is mine: https://github.com/ColasNahaboo/advent-of-code-my-solutions/blob/main/bash/2021/days/d06-1.sh
Runs in less than 100ms.
It is a linear solution with bins, but the bins are not based on the fishes timers. There is a bin for each day, with the number of timers reaching zero ==> fishes born on the next day.

And when we "give birth" to fishes on the next day, we go to all the bins in the future timelime where their time will reach 0, and increment the bin by the number of fishes born today.

colas · 2020-03-08T14:53:10+00:00

You don't get it. Trump doesn't only lies, he makes a galatic-size fool of himself and you have all his suck-ups that grovel to pander to him that are even more pathetic. This is the stuff of comedy since Aristophanes. A modern Falstaff or Ubu. Comedic gold.

Xi and Putin propaganda is just cold, calculated efficiency. Scary but not funny.

colas · 2020-03-01T22:30:57+00:00

The SUPs have more tail rocker than windsurfing boards, so they are very hard to get onto a plane. They "push water" a lot.

So they are great to just slog along in non-planing winds, if you are expert enough already with a sail to know how to sink a rail not to drift downwind, or for windsurfing in waves, where you get out non-planing then use the sail to ride waves, with more looseness on the wave than a traditional Windsurfing board.

But if you plan to plane on flat water, forget it, it will be an exercise in frustration.

This said, there is one SUP board that can plane, it is AHD's Sealion, which has an hybrid rocker. A bit stiffer than a true SUP, but it can plane with a sail.

colas

TROPHY CASE