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Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

adventofcode.com

111–120 of 226 posts

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#111
post #29

Earlier quoted context omitted.

Twelve nights of Christmas. Would also work better for me, calendar-wise :)

That would "require" a timeline shift for it to start on Christmas run until the Ephinany. Although I don't think anyone really knows what the 12 days of Christmas are anymore.

Yes, and I would be glad to see such a shift.

Shakespeare is still being read, I think.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#112
post #76

This is completely tangential but as someone who used to be a competitive programmer in the 2010s, I feel like this year marked the end of an era for me. I don't have time to do regular codeforces/atcoder/leetcode rounds (and the rampant AI cheating is pretty demotivating). So the big annual rituals for me to keep my "competitive programmer" label were: fb hacker cup, google code jam, topcoder TCO, and advent of code…

I get what you're saying, but Advent of Code isn't dead? The leaderboard is dead, but if that's an important part of it to you, I'm optimistic there'll be some nice large public groups you can join somewhere.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#113

Whenever there's a change like this, my gut reaction is to grieve and try to imagine ways that things could be kept the same. After thinking, "maybe puzzles could be designed by a group instead of an individual and they could share the work," I then thought, "and couldn't an LLM help?" And with that, I had to remind myself: Advent of Code isn't about there being 25 puzzles, and so maintaining volume at all costs has…

Hate to be the... whoever I'm being right now, but names have meaning. It's the reason to have them in the first place. > Advent of Code isn't about there being 25 puzzles, and so maintaining volume at all costs has nothing to do with it. It's the Advent of Code. Not "Random late year event with no religious / commercial tradition connotations whatsoever" of Code. The 25 is there in the name. It's the whole point :).

Advent is the four Sundays leading up to Christmas. 4 is in the name, not 25.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#114
post #61

Earlier quoted context omitted.

For Christian Advent to be exactly 25 days long, that would be a coincidence. Advent is not the time from December 1st until Christmas, it starts on whatever days the fourth Sunday before Christmas happens to fall on that year. This way, there are exactly four Sundays in advent. If Christmas itself should fall on a Sunday one year, it doubles as the fourth Sunday of Advent, i.e., then the first of Advent will be only…

Anyway, this is Western Christianity. In Eastern Christianity, the Nativity Fast starts on a fixed day: November 15.

Which happens to fall on November 28th, yes.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#115

Earlier quoted context omitted.

Hate to be the... whoever I'm being right now, but names have meaning. It's the reason to have them in the first place. > Advent of Code isn't about there being 25 puzzles, and so maintaining volume at all costs has nothing to do with it. It's the Advent of Code. Not "Random late year event with no religious / commercial tradition connotations whatsoever" of Code. The 25 is there in the name. It's the whole point :).

Advent is the four Sundays leading up to Christmas. 4 is in the name, not 25.

I thought it was meant to be like an Advent Calendar, which is normally 25.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#116

Earlier quoted context omitted.

I’ve been trying to design a puzzle for a game this year that humans can solve but LLMs can’t. I’ve come up with one, but it was hard work! It’s based around message cracking.

How many s are in the word

The bigger LLMs have generally figured out this specific problem.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#117
post #62

Earlier quoted context omitted.

Not necessarily. If they insist on there being only 12 puzzles, all they need to Save Christmas is to start the event on Christmas day, and rename it to "12 Puzzles of Christmas" or "Advent of Three Kings of Code", or such -- see: https://news.ycombinator.com/item?id=45710963 .

They could also publish the puzzles only every second day, I guess.

Or publish the harder version of the puzzle on a different day to the easier version.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#118
post #56

Earlier quoted context omitted.

This. The best I've ever achieved is maybe 15 puzzles on one year, with gaps for the days I missed. And this was when the puzzles were incrementally building upon implementing a bytecode interpreter, which was relatively little work per day. Once I miss my first day, playing catch up is an effort in vain, as the puzzles start taking 4+ hours to solve each, solving multiple in one day is a full-time commitment. Most a…

Yeah, totally this. I've had so much fun with AoC, learning nim, elixir at the same time. I would normally tap out around the same place on the first dynamic programming puzzle which just takes me so long to wrap my head around each time (tips anyone? :)). I welcome these new changes, and what ever the format are very greatful for all his hard work!

> tips anyone? :)

They're not as magical as they seem, you just need some practice. Read over the dynamic programming section in https://cses.fi/book/index.php (pdf link near the top is the free English version), then do a few on https://cses.fi/problemset/ . You'll be able to handle the AoC dynamic programming ones with _no_ problem at all.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#119
post #42
post #31

Earlier quoted context omitted.

I mean, wasn't pretty much the second half of all AoC exercises beyond LLM capabilities? I remember there being multiple accounts trying to one-shot AoC and all ended on day 10 or so.

[flagged]

It affects a certain disposition for the writer; the information it contains isn't in the actual data they are expressing, but rather the state of mind that they express it from, which can be important context. Oftentimes it can indicate exasperation, which is an important social queue to be able to pick up on.

A little excerpt from Arlo Guthrie

"I mean, I mean, I mean that just, I'm sittin' here on the bench, I mean I'm sittin here on the Group W bench, because you want to know if I'm moral enough to join the army, burn women, kids, houses and villages after being a litterbug."

Imagine that without the "I mean"s in it, and the importance of how they convey his stance on the situation.

Re: Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the first time

#120
post #3

One of the reasons I stopped participating was that as the second half of december was approaching I had less and less free time for solving the puzzles. So to me it is also a welcome change, I will try to finish it again this year.

For me I always had the time I just didn't have the ability. I solved all of them in 2017 but never really got close any other year.
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