[HN Gopher] Advent of Code 2025: Number of puzzles reduce from 2...
       ___________________________________________________________________
        
       Advent of Code 2025: Number of puzzles reduce from 25 to 12 for the
       first time
        
       Author : vismit2000
       Score  : 387 points
       Date   : 2025-10-26 08:19 UTC (14 hours ago)
        
 (HTM) web link (adventofcode.com)
 (TXT) w3m dump (adventofcode.com)
        
       | vismit2000 wrote:
       | From FAQ: "Why did the number of days per event change? It takes
       | a ton of my free time every year to run Advent of Code, and
       | building the puzzles accounts for the majority of that time.
       | After keeping a consistent schedule for ten years(!), I needed a
       | change. The puzzles still start on December 1st so that the day
       | numbers make sense (Day 1 = Dec 1), and puzzles come out every
       | day (ending mid-December)."
        
       | shrx wrote:
       | 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.
        
         | seabombs wrote:
         | Agree. It was getting in the way of me spending time with the
         | family because I was distracted mulling over the puzzles.
         | 
         | I had thought last year that they could peak the difficulty
         | around the middle of the month and bring it down a bit leading
         | up to the 25th. But just finishing it earlier is probably
         | better IMO.
        
         | jojobas wrote:
         | Doesn't help that the puzzles become increasingly tricky and
         | you can't just solve them as you sip your coffee anymore
         | (although some apparently can).
        
         | NoboruWataya wrote:
         | Same, I love AoC but I just never have time for them (December
         | is always the busiest time of year in my job).
         | 
         | I would have liked if a puzzle was released every 2 days though
         | so it still spanned the whole month. Would be more aligned with
         | the advent calendar concept. In fact in previous years the
         | puzzles have always had two parts so if that format is still
         | being retained there will still effectively be 24 puzzles.
        
           | emerongi wrote:
           | Spreading the two parts across separate days would be
           | interesting. There would be an extra element of trying to
           | predict what part 2 will be like.
        
           | KeplerBoy wrote:
           | Then again who has the time in the latter half of December?
           | 
           | I completed AoC on time every day once and let's just say it
           | wasn't a very pleasant experience. Very similar to sticking
           | to a too ambitious, too rigid gym schedule. Still time well
           | spent, but it sucks out all the joy.
        
         | rich_sasha wrote:
         | I once has this half serious idea to do "Advent of Parenting",
         | with one problem per month, and you start after Christmas. As
         | in, youre so delayed you start in the New Year, and have time
         | for one problem per month.
         | 
         | But hey I didn't have the time to do it. Kids...
        
           | Scarblac wrote:
           | When my kids move out, one of my plans is to finally start
           | the first Advent of Code.
        
             | skeeter2020 wrote:
             | you'll have a new set of excuses then, too.
        
         | mid-kid wrote:
         | 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 advents of code I've fallen off sharply after day 7-10, if
         | not sooner, and I'm pretty sure I'm not alone in this. I think
         | this is a welcome change.
        
           | runekaagaard wrote:
           | 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!
        
             | kadoban wrote:
             | > 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.
        
           | zrobotics wrote:
           | Most years, I end up finishing the puzzles in January. Same
           | reason- I end up missing a day due to schedule issues. Since
           | it's just a 'for fun' challenge, it isn't the end of the
           | world if you fall behind a bit. That said, this doesn't work
           | if you are doing this as part of a group.
        
         | confidantlake wrote:
         | 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.
        
         | ihuman wrote:
         | I wouldn't be surprised if the creator has metrics that show
         | that most people drop off around the halfway mark, for the
         | exact same reason
        
           | boccaff wrote:
           | You can see aggregated results on `stats` [1] for every year.
           | In general, half the people drop in the first 3-4 days. For
           | last year, by day 12 there is less than 1/5 of day 01. While
           | the stats do count people that completed later, the shape
           | appears to track well with what I saw during the events since
           | 2021.
           | 
           | [1] https://adventofcode.com/2024/stats
        
         | philipwhiuk wrote:
         | I have the opposite problem - I never get started until work
         | wraps up.
        
       | thomascountz wrote:
       | 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 nothing to do with it.
       | 
       | And aren't we so lucky that it isn't! Aren't we lucky to have had
       | the prior 500+ challenges given as gifts over the years! Aren't
       | we lucky to have a great demonstration of humility and care!
       | Aren't we lucky to have 12 new gifts to look forward to this
       | year!
       | 
       | Thank you!
        
         | petesergeant wrote:
         | 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.
        
           | ekimekim wrote:
           | There was one in a previous AoC that I think stumped a lot of
           | AI at the time because it involved something that was
           | _similar_ to poker with the same terminology but different
           | rules. The AI couldn 't help but fall into a "this is poker"
           | trap and make a solution that follows the standard rules.
        
             | petesergeant wrote:
             | Interesting! Maybe that's the general way to approach these
             | things
        
             | sunrunner wrote:
             | Was that 2023's Day 7 'Camel Cards' [1]?
             | 
             | [1] https://adventofcode.com/2023/day/7
        
             | gf000 wrote:
             | 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.
        
             | Cpoll wrote:
             | Isn't that easily solved by changing the terminology before
             | giving it to the LLM?
        
           | huflungdung wrote:
           | How many <$letter>s are in the word <word with $letters>
        
             | Crespyl wrote:
             | The bigger LLMs have generally figured out this specific
             | problem.
        
           | Gigachad wrote:
           | Have a look at https://arcprize.org/
           | 
           | They have hundreds of challenges that humans can solve in
           | under a minute which LLMs can not. Seems the general trend is
           | figuring out the rules or patterns of the challenge when
           | there are few examples and no instructions.
        
             | petesergeant wrote:
             | Ah, it also needs to be challenging for humans. It's a
             | prize to win something. I just didn't want people to throw
             | the question into Claude Code.
        
             | mewpmewp2 wrote:
             | Perhaps coding exercises that require 2d or 3d thinking, or
             | similar. This is where I have seen LLMs struggle a lot.
             | There are probably other areas too.
        
           | loeg wrote:
           | Just have to incorporate good judgement in some way.
        
           | LPisGood wrote:
           | For more examples of such problems check Jane street puzzles
           | of the month
        
         | thaumasiotes wrote:
         | > And with that, I had to remind myself: Advent of Code isn't
         | about there being 25 puzzles
         | 
         | Really? The name of the event is "Advent of Code". Having 25
         | puzzles is easily its most strongly-determined aspect.
         | 
         | You could argue for 23-29 puzzles, or perhaps for 5, but at 12
         | what's the name supposed to refer to?
        
           | eterm wrote:
           | Well advent calendars traditionally had 24 doors.
        
             | majoe wrote:
             | This lead me done a rabbit hole on wikipedia:
             | 
             | Advent calendars in their earliest forms were invented
             | approx. 80 years ago.
             | 
             | The four week advent period goes back to the 7th century
             | and was introduced by pope Gregory I..
        
               | thaumasiotes wrote:
               | > This l[e]d me done a rabbit hole on wikipedia:
               | 
               | > Advent calendars in their earliest forms were invented
               | approx. 80 years ago.
               | 
               | Well, Wikipedia starts its "History" section in 1945,
               | which is 80 years ago. But what it says about advent
               | calendars in 1945 is that they were lower-quality
               | reprints of earlier designs. This strongly implies that
               | they weren't a new concept in 1945.
               | 
               | The German wikipedia is more interested in the concept
               | and cites the word _Adventskalenders_ to the novel
               | _Buddenbrooks_ , which features one set in the year 1869
               | but was published in 1901. Either way, the calendars were
               | clearly an established cultural phenomenon well before
               | 1945.
               | 
               | Looking at the talk page (for the English article), it
               | seems that the history section was provided by a
               | "translation group" from their translation of a matching
               | section of the German article. It's not clear why they
               | began with the post-war period; the German page goes back
               | much further than that, which was also true at the time
               | they provided their translation. But this does explain
               | why the English "history" section begins by referring to
               | prior context that doesn't exist in the English article.
        
             | this_user wrote:
             | They still do in non-Anglo European countries where the
             | main celebration is held on the evening of the 24th.
        
           | matrss wrote:
           | IMO "Advent of Code" only determines the timeframe in which
           | it happens, not the amount of puzzles it must contain. It
           | could just as well be four puzzles, one for each sunday of
           | the advent, or any other amount, as long as they are released
           | within those roughly four weeks before christmas.
        
             | danielbln wrote:
             | Eh, the implication has always been that it's a Christmas
             | calendar where you open one door per day until it's
             | Christmas eve - just with code riddles instead of
             | chocolate.
        
               | roetlich wrote:
               | > one door per day until it's Christmas eve
               | 
               | That would be 24.
        
               | thaumasiotes wrote:
               | You also open one on Christmas. Some people consider
               | Christmas more important than Christmas eve.
               | 
               | https://www.hallmark.com/house-and-
               | home/figurines/precious-m...
        
               | atq2119 wrote:
               | That really depends on which country you're in.
        
           | akho wrote:
           | Twelve nights of Christmas. Would also work better for me,
           | calendar-wise :)
        
             | ThunderSizzle wrote:
             | 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.
        
               | TeMPOraL wrote:
               | We have a thing called "Three Kings" (aka. "three wise
               | men") in Poland, that falls on Jan 6th. If My Math Is
               | Correct(tm), there's 12 days between the Christmas day
               | (Dec 25th) and Jan 6th, so maybe the song is about this
               | period?
        
               | dinkelberg wrote:
               | Epiphany (GP had a typo) and Three Kings is the same
               | occasion, in fact. Wikipedia:
               | https://en.wikipedia.org/wiki/Epiphany_(holiday)
        
               | akho wrote:
               | Yes, and I would be glad to see such a shift.
               | 
               | Shakespeare is still being read, I think.
        
             | pfortuny wrote:
             | This referes to the feast of the Epiphany, though, which is
             | 12 nights _after_ Christmas...
        
               | akho wrote:
               | That's why I say it would've worked better for me, yes.
        
           | bigstrat2003 wrote:
           | No, Advent means that it goes for the four weeks prior to
           | Christmas. It doesn't mean "one thing each day" during that
           | duration.
        
             | thaumasiotes wrote:
             | https://en.wikipedia.org/wiki/Advent_calendar
             | 
             | Minimum one, sometimes two.
             | 
             | (Also, Advent doesn't mean four weeks. Christmas might fall
             | on a Monday.)
        
           | riffraff wrote:
           | I assumed it was "twelve days of Christmas"- related
        
           | thomascountz wrote:
           | I'm not arguing this point. I conceit, I thought the
           | sentiment was obvious. If it wasn't--and if read literally--I
           | thought that that statement was the weakest and most
           | uninteresting part of what I shared. However, to my surprise,
           | this statement, and its specific interpretation, is what
           | people found compelling!
        
         | TeMPOraL wrote:
         | 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 :).
        
           | zeroCalories wrote:
           | Well, Christmas is cancelled this year I guess :(
        
             | TeMPOraL wrote:
             | 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.
        
               | kleiba wrote:
               | They could also publish the puzzles only every second
               | day, I guess.
        
               | TeMPOraL wrote:
               | Give a kid half of an advent calendar and tell them to
               | open the window every second day, let's see how long
               | it'll keep their interest (I expect much less than 12
               | days) :). That's not how Advent Calendars work!
        
               | pajamasam wrote:
               | We're not kids though...
        
               | Dilettante_ wrote:
               | Let your hair down man, it's christmas!
        
               | riffraff wrote:
               | That was my first thought too, and I'd prefer it, cause
               | sometimes I'll get stuck on a problem, or I'm busy, or I
               | forget, and I'd rather have one more day. Bur it's Eric's
               | call in the end.
        
               | robertlagrant wrote:
               | Or publish the harder version of the puzzle on a
               | different day to the easier version.
        
           | kleiba wrote:
           | 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 three weeks earlier.
        
             | TeMPOraL wrote:
             | All correct. Which is why I said religious slash
             | _commercial_ tradition - Advent is first and foremost just
             | another sales event, and for convenience of sellers and
             | buyers ( _and_ their children) the commercial advent got
             | regularized to 25 days, so the stock of calendars that
             | failed to sell last christmas season can be put up to sale
             | in the coming one.
        
               | kleiba wrote:
               | Agreed, I didn't mean to critique you!
        
               | TeMPOraL wrote:
               | I appreciate you working out the math above! :).
               | 
               | (I never could wrap my head around all this. I had enough
               | problems with Easter events, where the math makes a
               | detour through a Lunar calendar.)
               | 
               | EDIT: And my memory of the Tradition is wrong too, it's
               | supposed to be 24 - as confirmed by
               | https://news.ycombinator.com/item?id=45710618, and
               | corroborated the two "Paw Patrol" themed Advent Calendars
               | I just found still stashed in my home office.
        
               | kleiba wrote:
               | The Sunday after the first full moon after March 21st
               | (first day of spring) - what could possibly be confusing
               | about that?!
               | 
               | j/k ;-)
        
               | TeMPOraL wrote:
               | I still find it easier to explain it as "14 Nisan *
               | _energetic hand wave_ *!!" :).
        
               | SJMG wrote:
               | Since we're all being exacting here... =p
               | 
               | > (first day of spring)
               | 
               | It's actually the March equinox. "Spring" is true only in
               | the northern hemisphere. What's more it's the
               | _ecclesiastical_ equinox, not the astronomical equinox,
               | whose date actually varies depending on the year.
               | 
               | Never mind that all this is descriptive of dating in
               | countries that grew up with Western Christianity.
               | Countries where Eastern traditions dominate often date it
               | differently.
               | 
               | All good will to you both = )
        
               | kleiba wrote:
               | +1 from me!
        
               | geerlingguy wrote:
               | If I were Christmas of code, it would start mid-June and
               | end on Christmas Eve!
        
               | TeMPOraL wrote:
               | You're forgetting about Halloween, Black Friday/Cyber
               | Monday, and the most recent Singles Day (11.11); the
               | Commercial Calendar is steadily squeezing the Christmas
               | Season into December and out of the rest of the year!
        
               | timeon wrote:
               | Commercial Halloween starts during October just after or
               | parallel with October-fest. It ends before end of October
               | because people buy things for an event before it starts.
               | End of Halloween is when Commercial Christmas starts.
               | 
               | There is no time for actual advent or winter calmness in
               | general.
        
               | Ekaros wrote:
               | Wouldn't winter calmness be January or February, maybe
               | March? You know coldest time in general on Northern
               | Hemisphere?
        
               | timeon wrote:
               | I think you are right, that seems to be the case.
        
               | tjr wrote:
               | I decided to indulge in a Dunkin' pumpkin donut this
               | morning, what with it being late October and the weather
               | actually now fall-like. Apparently they have already
               | discontinued them!
        
               | toast0 wrote:
               | > the Commercial Calendar is steadily squeezing the
               | Christmas Season into December and out of the rest of the
               | year!
               | 
               | We can only hope. The Christmas song containment fields
               | are weakening as we speak.
        
               | tialaramex wrote:
               | Right, my local grocery store moved Halloween stuff to
               | where Diwali stuff was near the front of the store, and
               | immediately put Xmas stuff where the Halloween stuff used
               | to be, in a week's time it'll be a whole aisle of Xmas.
        
             | bananaflag wrote:
             | Anyway, this is Western Christianity.
             | 
             | In Eastern Christianity, the Nativity Fast starts on a
             | fixed day: November 15.
        
               | akho wrote:
               | Which happens to fall on November 28th, yes.
        
           | bigstrat2003 wrote:
           | Technically the event needs to go for a certain number of
           | days, but Advent doesn't mean puzzles must come every day.
           | They can do puzzles every 2-3 days if they want to.
        
           | Trasmatta wrote:
           | > The 25 is there in the name. It's the whole point :).
           | 
           | You're overly attached to the meaning of Advent, but you
           | aren't even aware of the meaning. It doesn't mean exactly 25.
           | This year Advent Sunday is November 30th.
           | 
           | And the creator of Advent of Code can do whatever they want
           | with it, despite the name. They've put an immense amount of
           | effort into this for so long - if that had been me, I would
           | have been incredibly disheartened to see people saying "the
           | whole point is just 25".
        
           | Sharlin wrote:
           | If, as you claim, the association of 25 to "advent" is
           | primarily commercial, that's much more of a reason to avoid
           | that association. In any case it's very culture-specific. In
           | many countries, including mine, Christmas Eve is the "main"
           | event that people look forward to, and the number of "advent
           | days" in calendars and such is 24. On the other hand,
           | ecclesiastically there are four Advent Sundays, and the
           | number of days is thus variable and also not really
           | pertinent.
        
           | akerl_ wrote:
           | There are tons of advent calendars commercially sold that
           | have fewer than 25 slots.
           | 
           | It's safe to say this ship has sailed.
        
           | looperhacks wrote:
           | > The 25 is there in the name.
           | 
           | This largely depends on who you're asking? I don't know
           | anyone who wouldn't consider 24 the course correct number of
           | Advent, simply because that's the common number here (we
           | celebrate Christmas on the 24th). So 12 makes perfectly
           | sense, just do every second day.
           | 
           | There are also many groups who don't start on the 1st of
           | December, but on the first Sunday of Advent. And probably
           | many others.
        
             | crote wrote:
             | Advent calendars are used to count down the days. Doing one
             | every _other_ day defeats the purpose.
        
               | shortrounddev2 wrote:
               | I thought the purpose was to be a fun thing we used to
               | kill time over the holidays
        
           | wodenokoto wrote:
           | Advent is the four Sundays leading up to Christmas. 4 is in
           | the name, not 25.
        
             | robertlagrant wrote:
             | I thought it was meant to be like an Advent Calendar, which
             | is normally 25.
        
               | dangrie158 wrote:
               | Not in all traditions. E.g. in Germany Christmas Eve is
               | typically the last day so you only get 24.
        
               | tcshit wrote:
               | Yeah, in Sweden too.
        
               | elygre wrote:
               | Norway, too.
        
               | hnlmorg wrote:
               | And even in the places where it's 25 days, there's plenty
               | of advent calendars that only have 12 doors - though
               | they're typically budget versions of expensive calendars
               | (eg a dram of whisky behind each door)
        
               | mckn1ght wrote:
               | Falsehoods programmers believe about time #604: all
               | advent calendars have 25 slots
        
               | Fnoord wrote:
               | Winter Solstice is usually (not always) on 21th December.
        
               | bcraven wrote:
               | https://www.lego.com/en-gb/holiday-gifts/advent-calendars
               | 
               | 24 doors on the Lego calendars too
        
             | theodpHN wrote:
             | Yep, Advent wreaths have 4 candles, so there's wiggle room
             | to reduce the frequency further.
             | 
             | https://en.wikipedia.org/wiki/Advent_wreath
        
             | anamexis wrote:
             | Advent is a liturgical season, not a set of 4 Sundays.
             | Neither 4 nor 25 are "in the name."
        
             | misja111 wrote:
             | Advent comes from the Latin word adventus, which means
             | "arrival" or "coming." It refers to the coming of Christ.
             | There is no 4 in the name, no 24, 25 or whatever else.
        
           | klausa wrote:
           | You need to turn in your polish passport for publicly saying
           | that the advent is 25, not 24 days ;P
        
             | porphyra wrote:
             | To be fair in the original Advent of Code the last day is
             | just a freebie and not a real programming problem.
        
               | tialaramex wrote:
               | Right, mini-spoiler if you've never reached 50 stars for
               | a year:
               | 
               | The 50th star is awarded for having the other 49 stars
               | and then basically clicking OK I think. If you've been
               | diligently solving them in order, it means you
               | effectively get two stars for your final 49th puzzle of
               | the year on Christmas Day, which makes sense because then
               | the puzzles are very hard and a "normal" puzzle wouldn't
               | leave much time for other Christmas Day activities. But
               | if you're the sort of person who often gives up on a day
               | and never comes back you may never have seen this because
               | you never got to 49 stars.
               | 
               | You're not quite right that the Christmas Day puzzle is
               | trivial - it's the first half of a maybe week 1 type
               | difficulty puzzle, but there just isn't a second half:
               | 
               | Here's the puzzle text for last year's Xmas Day (if you
               | are logged in you can play, but even without it will
               | explain the puzzle it just won't give you an input to
               | test your solution):
               | 
               | https://adventofcode.com/2024/day/25
        
             | jvanderbot wrote:
             | Right so since each problem has more than one part, we are
             | back to advent of 24 problems.
        
             | jayknight wrote:
             | Really though, for Catholic and protestant churches, Advent
             | starts the fourth Sunday before Christmas, so isn't always
             | the same length. In Orthodox Churches, Advent is 40 days
             | (starting Nov 15) just like Lent.
        
           | hitarpetar wrote:
           | > Hate to be the... whoever I'm being right now
           | 
           | the word you're looking for is pedant
        
             | collingreen wrote:
             | "pedant who didn't look up their own point or consider
             | other world perspectives before boldly declaring that the
             | way they thought about it first was the only true way"
             | 
             | In the spirit of pedantry, I added even more minor detail!
        
           | paulcole wrote:
           | > Hate to be the...
           | 
           | You don't seem to hate it that much?
        
           | celticninja wrote:
           | Advent does not mean 25. It just means 'the coming', so 12,
           | 25, 1, 8 are all acceptable lengths. And if you reay need it
           | to be 24 you can calm it 0.5 per day.
        
             | oytis wrote:
             | It's a reference to a German tradition of Advent Calendar
             | with 24 small doors. Every day from 1st to 24th of December
             | children would open one door and find a candy, a picture, a
             | small toy, a quest etc. depending on calendar's theme
        
               | celticninja wrote:
               | I get it, but Advent calendars are not just German. I am
               | pretty sure they are common all over the western world
               | where Xmas is celebrated. But Advent doesn't in any way
               | mean 25.
        
           | throwingrocks wrote:
           | Geez. Do you really think the number matters? I would be
           | grateful to the creator even if it was 3 days.
        
         | gs17 wrote:
         | I think the easiest way to have 24/25 of something would be to
         | have the "part 2" for each puzzle get released the next day. It
         | would probably ruin the momentum about as much as having days
         | off would (as another alternative to make the timing fit
         | "advent"), but there could be a fun extra layer of puzzle with
         | a hint of what the part 2 will be so people can try to
         | speculate and modify their code in anticipation.
        
           | boccaff wrote:
           | I am not aware of Eric saying something about that
           | alternative, but this comment on reddit[1] makes a lot of
           | sense to me:
           | 
           | > Given that part 2 is often a very simple modification of
           | part 1, this could lead to many of the days being total
           | letdowns. I can enjoy a simple puzzle, but I'd be a bit
           | disappointed if one day is a single line change to the
           | previous day.
           | 
           | I'd also add that not having to be worried everyday about
           | something makes a lot of sense. He can have fewer days "on
           | call" in December with.
           | 
           | [1]https://www.reddit.com/r/adventofcode/comments/1ocwh04/cha
           | ng...
        
       | nikanj wrote:
       | Tryhards ruin everything, part n
       | 
       | Make a fun little christmas calendar to bring joy to the people,
       | get turned into a gamified warzone where people use AI and bots
       | to try to get onto the global leaderboards - possibly because
       | getting on them might net you a job at FAANG
        
         | iamflimflam1 wrote:
         | People - the reason why we can't have good things.
        
         | fjfaase wrote:
         | The temptation to start a competative private leader board will
         | be great, just for the mentioned reason. I have a reference my
         | scores in my CV. The competative part of AoC is one of the
         | things that I find attractive and also has taught me some
         | valuable lessons about coding, like taking some time to review
         | the code the first time before submitting. I experienced
         | several times that I spend of time to debug a small bug due to
         | a minor error, that I could have caught had I spend some time
         | reviewing. Especially with the first puzzles, I try to get it
         | right the fitst time with respect to compiling and execution.
         | 
         | I will search for a pure C private group to join that only
         | allows a small library for things like reading the input as an
         | array of strings.
        
           | 0x264 wrote:
           | On your CV ? Has any recruiter or hiring manager ever
           | commented on it, or said the mention gave you an advantage ?
        
             | fjfaase wrote:
             | No, but I don't care. I guess that most hiring managers do
             | not know what AoC is.
             | 
             | Next week, I will be 64, and I am no longer searching for a
             | full time job. In the past decade I only worked for 24 or
             | 30 hours per week. I am financial independent and plan to
             | only work freelance if there is some opportunity.
             | Currently, I am not actively searching for a job.
        
           | fjfaase wrote:
           | I have created a private leaderboard which you can join with
           | `1563228-d419ba6d.`
           | 
           | The basic rule is: you are only allowed to use code you wrote
           | yourself. That does include code you wrote before the start
           | of the contest, for example, standard functions you wrote for
           | earlier AoC editions.
        
         | ozim wrote:
         | Fun part is that world mostly doesn't really work like that and
         | they don't really get the job.
        
         | Udo wrote:
         | I know this is an outsider position, but I always felt that the
         | AoC leaderboard was a mistake. Very few people had the time,
         | the commitment, and the capability of making it on there in a
         | meaningful fashion, and it put an emphasis on something that
         | didn't match the vibe of the event at all. If speedrunning the
         | problem solving was the point, then why package every episode
         | into an enjoyable little story?
         | 
         | This also ties into the comments that AoC has become moot or
         | was "ruined by LLMs". If you enjoy solving the problems,
         | nothing should have changed for you. What's the difference if a
         | given problem was already solved by an LLM, or a group of IQ
         | 200 superhumans from MIT for that matter?
         | 
         | As time marches on, there will eventually be absolutely nothing
         | left where an unaugmented human outperforms a machine. That
         | doesn't mean you have to stop enjoying things. In a few years
         | at most, all programming will be purely recreational.
        
           | robryan wrote:
           | I liked the leaderboard prior to AI. Was fun to click through
           | to various profiles and see who was in there and what their
           | solutions looked like.
        
           | bigstrat2003 wrote:
           | > In a few years at most, all programming will be purely
           | recreational.
           | 
           | That's a bold prediction given how much LLMs suck at
           | programming today (and haven't really improved, either). I'm
           | willing to believe that we will someday invent an AI that can
           | program better than humans. I don't believe it'll be within a
           | few years, because the current architecture shows no signs
           | that it'll ever be able to get the job done.
        
         | tjpnz wrote:
         | You can put that on your resume and I guarantee nobody will
         | check.
        
       | lexicality wrote:
       | I see the leaderboard is gone too. Unfortunate but entirely
       | predictable given how the last 2 years went.
       | 
       | That being said, I was worried he'd cancel the entire thing, so
       | this is still good news!
        
         | mid-kid wrote:
         | >predictable given how the last 2 years went
         | 
         | QRD? Was it AI?
        
           | lexicality wrote:
           | Yeah, a bunch of people started going on witch hunts against
           | the people where were obviously using AI (eg ~30 second solve
           | times) and also anyone who had "AI" anywhere in their bio.
           | 
           | IMO the levels it got to was wildly out of proportion, even
           | if these people were cheating (say what you will about AI,
           | but if the rules say not to use it and you do: you're a
           | cheater) but maybe I would have felt differently if the
           | timezones meant I could take part, rather than waking up to
           | drama.
        
             | 10hr wrote:
             | sounds like the competition had challenges even before AI
             | or any rules about AI or not.
             | 
             | I never followed this challenge aside from doing a few 10
             | years ago in college.
             | 
             | If speed to problem completion matters though, then
             | question release time will be brutal for some.
        
         | WJW wrote:
         | The leaderboard has led to the same predictable discussion for
         | as long as the AoC has existed. Recurring themes:
         | 
         | - The puzzles get published in the middle of the night for most
         | of Europe, can't we have a better system like scoring on
         | <arbitrary other metric the poster likes better>.
         | 
         | - It's weird that many of the pages say "just have fun, it's
         | not a race" and then also there's a prominent leaderboard page
         | to show who's currently ahead in the race.
         | 
         | - There's been people taking the whole thing way too seriously
         | from basically year 1, trying to load their puzzle input as
         | fast as possible by polling every 10 ms and putting too much
         | load on the servers.
         | 
         | - Whether AI is allowed is always a super toxic discussion with
         | no real outcome because you can't enforce it.
        
           | emil-lp wrote:
           | 6am or later for most of Europe is not middle of the night.
        
             | tgv wrote:
             | Then it's the middle of the night for the Americas...
        
             | layer8 wrote:
             | Yes it is. ;)
        
             | andix wrote:
             | 6am is the middle of the night for most software developers
             | ;)
        
               | surajrmal wrote:
               | If they don't have children maybe.
        
               | andix wrote:
               | It's a tough decision: AoC or kids.
        
         | matsemann wrote:
         | Gonna miss it. So fun to see how fast one can parse the
         | problem, figure out how to solve it while thinking of edge
         | cases, and then actually write and run it. I've never been high
         | up on the leaderboard, but enjoyed waking up early in December
         | and give it a crack. Most often rank ~1000, a few times ~100.
         | 
         | But I also understand the decision. Fun while it lasted, but
         | I'll find other ways to have fun with AoC this year!
        
       | aronhegedus wrote:
       | I've participated in the past, and felt like I always drop off
       | around day 18+ because of holidays etc.
       | 
       | I personally also didn't like when part II of a question felt
       | like a completely new question, instead of a neat extension of
       | the previous one.
       | 
       | I am very happy that this is something that's available to do,
       | for free though. I see advent of code as a good excuse to dabble
       | with a new language, usually with a few people from work.
        
       | defanor wrote:
       | On the bright side, this will lead to a more relaxed December
       | schedule. I do not compete for the leaderboard, but trying to
       | solve the puzzles on the days they are released (to keep it in
       | the spirit of an advent calendar), and the puzzles towards the
       | end sometimes take me a considerable chunk of the day to solve,
       | which is tricky to combine with the regular schedule, and may be
       | rather stressful (though still a nicer kind of "stressful", as
       | you get on celebrated holidays).
        
         | sunrunner wrote:
         | This matches my experience, and I've been 'nervously'
         | anticipating this year's Advent of Code. I managed to keep to
         | the spirit last year and get everything done by Christmas day
         | (though admittedly with some days bleeding over into other days
         | due to pesky family/other commitments), but even this relied on
         | having the last week or so of the month be relatively free for
         | me.
         | 
         | While I've usually been able to do the first half of the
         | month's puzzles in the day before breakfast, over lunch and in
         | the evening, the increasing difficulty does mean that later
         | puzzles can really eat into a day, particularly if you happen
         | to go down a bad path for your solution.
        
       | sunrunner wrote:
       | I genuinely look forward to Advent of Code every year (whatever
       | that says about me) and next year's one is always on my mind, so
       | naturally I'm somewhat sad about this as the one-puzzle-a-day up
       | to Christmas day just felt very neat, and I liked the mostly
       | gentle initial difficulty curve up to the more 'spiky' questions
       | later.
       | 
       | Having said that, having done a few years now I think the
       | following things end up feeling consistent across years:
       | 
       | The first 10-ish (give or take) days were always simple enough
       | that experienced programmers can likely spit them out during
       | their daily standup. This isn't bad, as I think they're _great_
       | for newer programmers to get a bit of algorithmic and data
       | structure thinking practice, but they can definitely feel a bit
       | same-y once you 've done a few years. This isn't a critique of
       | how AoC was structured, just an observation of how it can feel
       | after you've seen a few years. Having said this, I'm sure I'll
       | miss the gentle warm-up this year.
       | 
       | I wonder what this means for the difficulty curve i.e. the
       | almost-inevitable path-finding question will appear on Day 5 and
       | not Day 15?
       | 
       | I'm sure Eric has thought this through but I wonder if an every-
       | other-day approach (perhaps with a 'softer' puzzle for Christmas
       | day itself) would be popular, as I imagine people balancing a job
       | and/or family while wanting to do this might appreciate having
       | two days for the more challenging later puzzles.
       | 
       | On the other hand, free time for this generally does get more
       | tight as you get closer to the end of the month and the puzzles
       | get more challenging, so this approach does just make a chunk of
       | space for people later in the month, and individuals can choose
       | to keep up with the puzzles on release day if they can or just
       | not worry about it and let things roll over.
       | 
       | Unfortunately, I guess I'll have to actually go and see my family
       | this Christmas instead of ignoring the mandatory visits, which
       | seemed like a fair sacrifice to keep up with calendar ;)
       | 
       | > It takes a ton of my free time every year to run Advent of
       | Code, and building the puzzles accounts for the majority of that
       | time. After keeping a consistent schedule for ten years(!), I
       | needed a change.
       | 
       | Completely fair. As Eric says in some of his presentations on
       | this it takes him about three or four months of his spare time,
       | so this is more than understandable. Props to him for keeping
       | this up consistently with his day job for the last ten years.
       | 
       | > The global leaderboard was one of the largest sources of stress
       | for me, for the infrastructure, and for many users.
       | 
       | I don't mind this so much personally (outside of a morbid
       | curiosity in the really fast participants) although I know people
       | that were really invested in it, but there were some genuine
       | points of contention for people that _were_ interested in the
       | leaderboard:
       | 
       | - The global puzzle unlock time, while explained by Eric himself
       | in his presentations, does make being on the leaderboard
       | impractical for people outside of time zones where the actual
       | release time is friendly for that. For me it's 5am, and the only
       | time I ever came even close (while also being nowhere near...)
       | was when I happened to be up at that time due to insomnia (not
       | caused by AoC).
       | 
       | - It sounded like an infrastructural point of pain as the single
       | global release time coupled with submissions-by-country-size and
       | how keen some of the puzzle solvers are makes for a great initial
       | traffic burst with a long tail (also mentioned on the behind-the-
       | scenes videos).
       | 
       | - It naturally favoured people with an interest in these kinds of
       | puzzles, so the selection bias in the leaderboard is inherently
       | skewed towards a) the subset of people that are choosing to do
       | this out of genuine personal interest and then b) the subset of
       | _those_ that are likely to also be interested in competitive
       | programming-type challenges. This is natural, but I think it does
       | make the leaderboard less relevant for the majority of
       | participants.
       | 
       | - The inevitable contention of the use of 'AI' just to be on the
       | leaderboard
       | 
       | Anyway, I'll just end this with a thank-you to Eric himself for
       | designing and running this consistently for the last ten years as
       | it's something I've come to really enjoy, the community is very
       | lucky to have this, and I hope these changes make it possible for
       | him to continue doing this with lower physical costs to him
       | personally and perhaps lower stress for the participants that
       | just enjoy the puzzles for learning and the rare opportunity to
       | write simple programs to solve problems.
       | 
       | For interested watchers:
       | 
       | - 'Eric Wastl - Advent of Code: Behind the Scenes' -
       | https://www.youtube.com/watch?v=_oNOTknRTSU
       | 
       | - 'Keynote: Advent of Code, Behind the Scenes - Eric Wastl' -
       | https://www.youtube.com/watch?v=uZ8DcbhojOw
       | 
       | Edit: Typos
        
       | cod1r wrote:
       | This is sort of a bummer but as long as Eric feels less stressed
       | and more happy, I'm all for it.
        
       | kykat wrote:
       | why not a puzzle every two days instead of ending it mid-
       | december?
        
         | exegete wrote:
         | You will have that option
        
         | 0x264 wrote:
         | You can definitively play like that if you want to. At day 2n
         | (n > 0) you do the puzzle of day n.
        
       | HiPhish wrote:
       | If he has cut the number of puzzles in half, why not then release
       | a new puzzle every other day? That would make more sense because
       | AoC would still run until Christmas, and it would give people
       | more time per puzzle. Maybe unlock part 2 of each puzzle the day
       | after the puzzle has been posted, so there still something new
       | every day.
       | 
       | I once tried participating, but gave up halfway through because
       | one puzzle per day was just too much time. If it was one puzzle
       | every two days it would be more manageable.
        
         | akerl_ wrote:
         | If they're released every day for 12 days, you can do a puzzle
         | every other day.
         | 
         | If the were released every other day, people who wanted to do
         | them for 12 straight days could not.
        
           | rootlocus wrote:
           | > If the were released every other day, people who wanted to
           | do them for 12 straight days could not.
           | 
           | If they instead waited 12 days, they could start with the 6
           | puzzles already released, and then have enough puzzles to
           | solve once a day for the next 12 days.
        
       | rawling wrote:
       | https://news.ycombinator.com/item?id=45665217
        
       | gooodvibes wrote:
       | No more leaderboard too!
       | 
       | These look like positive changes, a 2x longer event isn't 2x more
       | fun or 2x more satisfying to participate in.
       | 
       | After skipping the past couple of years, I feel like I'm more
       | likely to give it a go again this year.
        
       | klustregrif wrote:
       | Really appreciate thise changes! Both the reduction in puzzles
       | which means less work, but overall I don't think it's going to
       | make the event less fun.
       | 
       | And removing the global leaderboard is good, rather than trying
       | to police how people solve the puzzles just let people have fun
       | on their own boards with people they know.
        
       | sandruso wrote:
       | Big AoC fan these are welcomed changes. I've always started
       | strong but fell off as it was increasingly more difficult to
       | solve puzzles during nighttime. And after you miss one you kinda
       | loose the streak.
       | 
       | This year I'm going to combine it also with mine noaidecember
       | challenge to get a little more dopamine from problem solving.
        
       | bilsbie wrote:
       | Last year a lot of the problems were multi steps. Why not just
       | break up the steps and get to 25?
       | 
       | Also after day three I fell hopelessly behind. 12 might be fine.
        
       | mkovach wrote:
       | Awesome!
       | 
       | Yy usual 5-to-7-day output scramble will now look vastly more
       | competent, ah, well, complete. Not actually be smarter, mind you,
       | but radiate the comforting glow of effort by someone who has
       | their temporal ducks in a suspiciously photogenic row.
       | 
       | Improvement? No. But the illusion of improvement? Practically
       | Nobel-worthy. I'm already enjoying this change.
        
         | TeMPOraL wrote:
         | I'm not sure how to parse all this, but I really appreciate the
         | mental image of temporal ducks in a photogenic row. Sounds
         | great for my Star Trek themed, _very_ slow Sunday morning.
        
           | mkovach wrote:
           | Been toiling with a new client, ingesting their
           | documentation, and improving it with a Hitchhiker's Guide
           | twist, so the next person needs less caffeine and weeps less.
           | 
           | It is bleeding into other aspects, but it's my pleasure to
           | help with your Sunday morning imagery!
        
       | few wrote:
       | 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. Now besides hacker cup, the rest are dead.
       | 
       | Sad. :(
        
         | npinsker wrote:
         | 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.
        
       | kevinwang wrote:
       | A little sad for me because I've enjoyed the global leaderboard
       | aspect for years but of course my second reaction has to be to
       | take a step back and appreciate all the joy that this one man has
       | given us for all these years.
       | 
       | And he's made it clear from that start that he never intended the
       | global leaderboard to be the point, plus AI the last few years
       | messes it all up. All good things come to an end, and I gotta
       | appreciate the good run that we had, and the voluntary work of
       | one person that gifted it to us.
        
         | timeon wrote:
         | Based on time-zone, it wasn't really _global_.
        
       | 12345hn6789 wrote:
       | End of an era. Thank you! It was a blast.
        
       | spion wrote:
       | I wonder if it would've felt more natural if the "part 2s" of the
       | puzzles became separate days instead. (Still 12 days worth of
       | puzzles, but spread out across 24 days, with maybe one extra,
       | smaller, easier puzzle for the last day to relax)
        
         | Cupprum wrote:
         | I was thinking the same! This would be great , have a puzzle
         | each other day. But i trust the organizers are going to do a
         | great job and we will have fun either way.
        
         | matsemann wrote:
         | Then the 24h between part1 and part2 could be spent trying to
         | predict what part2 will be, or generalize the solution to see
         | if you can handle whatever part2 throws at you. For instance
         | the lanternfish ( https://adventofcode.com/2021/day/6 ) one
         | would expect to just have a higher number, so if one solved
         | part1 iteratively one could make an educated guess for a fast
         | part2 solve.
        
       | testdelacc1 wrote:
       | Last year was the first time I completed all 25 and I was looking
       | forward to reprising that. It's alright. I guess I could always
       | try older problems.
        
         | radiator wrote:
         | That is a healthy attitude. I wonder if everyone "missing" AoC
         | has already solved all the past problems.
        
       | Insanity wrote:
       | Although number of puzzles != time investment, selfishly I'm down
       | for this change. As I get older it's harder to find time to
       | complete them, so I'm hoping this also relieves some of the
       | (artificial) pressure to keep up with daily puzzles by decreasing
       | the time spent per day.
        
       | thrance wrote:
       | I did exactly half of the puzzles last year, and I think my case
       | is not too uncommon. I am perfectly fine with this, only maybe it
       | would be slightly better if the puzzles came out every two days
       | instead, to ward off the FOMO and give us more time per puzzle?
        
       | Fnoord wrote:
       | > If you're still stuck, maybe ask a friend for help, or come
       | back to the puzzle later. You can also ask for hints in the
       | subreddit.
       | 
       | Not sure why this is OK but prompt engineering isn't? If someone
       | wants to test that skillset, let them be instead of asking
       | 'please don't'. Especially given the competitive nature is now
       | optional.
        
       | makach wrote:
       | Appreciate it, for me it became this stress inducing xmas
       | calendar. Did it a couple of years and then I stopped because it
       | wasn't fun anymore. Some puzzles were really hard and I took it
       | really personally when I couldn't complete them.
        
       | andix wrote:
       | I love it, starting mid-december a lot of my free time goes into
       | Christmas preparations and at the same time the puzzles went up
       | in difficulty. I never made it past #18 in real time. Not because
       | of the difficulty, I just had to do other things.
       | 
       | Another option would be to add some breaks, maybe a day off every
       | 2 or 3 days.
        
       | phforms wrote:
       | It is unfortunate, but I can absolutely understand it. Keeping up
       | such open-ended, time-consuming projects year after year while
       | the person doing it changes inevitably - their personal life,
       | habits, job, interests, etc. - must feel like a burden at some
       | point, even if it is out of love and passion (I know that from
       | personal experience with my voluntary work, from which I had to
       | take a break after 10+ years).
       | 
       | I am truly thankful for all of Eric Wastls work on Advent of
       | Code, no matter how much time he can invest and how much puzzles
       | we get. I already look forward to the challenge at the start of
       | autumn and consider what programming language I will choose (this
       | year it'll be Uiua :)). I am very slow at these puzzles, so I
       | mostly quit at around puzzle 12 anyway, but I learn so much from
       | them and they are a lot of fun.
        
       | rileytg wrote:
       | This prompted me to try out claude code on last years... To
       | absolutely no surprise, it looks like the model was trained on
       | advent of code. For the day 2 challenge, I put in this prompt:
       | for each row in input.txt, identify all the rows where: 1. the
       | columns either all increase or decrease 2. the increase/decrease
       | is >1 and <4. count total # of rows that match this. write a
       | python script
       | 
       | It solved it very quickly. However...
       | 
       | It's solution code included this comment:                 Check
       | if a report is safe based on two criteria:
       | |       |     1. All levels must be either all increasing or all
       | decreasing
       | |       |     2. Adjacent differences must be between 1 and 3
       | (inclusive)
       | 
       | This is odd because I never mentioned reports or levels...
       | However the challenge does:                 The unusual data
       | (your puzzle input) consists of many reports, one report per
       | line. Each report is a list of numbers called levels that are
       | separated by spaces. For example:
        
         | rileytg wrote:
         | Follow up:                 > how did you know to call them
         | reports and levels?            Good catch! I noticed that
         | terminology in the input file structure. When I read input.txt,
         | I saw the data format - each row       contained multiple
         | space-separated numbers.            I actually made an
         | assumption based on common Advent of Code patterns (this looks
         | like a typical AoC problem structure). The terms
         | "reports" and "levels" aren't explicitly stated in your
         | requirements - you just said "rows" and "columns".            I
         | should have used more generic terms like:       - "row" instead
         | of "report"       - "values" or "numbers" instead of "levels"
         | Would you like me to update the script to use more neutral
         | terminology that matches your original description?
        
       | thomasqbrady wrote:
       | This is fantastic in every way. The hardest part of participating
       | for me was finding more time closer to the holidays as the
       | challenges got harder. Fewer, better challenges, with more space
       | between them and the end of the year is a brilliant solution. So
       | excited and grateful.
        
         | simmonmt wrote:
         | Fewer challenges, but no more space between them. They still
         | come out daily starting December 1st. They just stop coming
         | sooner.
        
       | axpy906 wrote:
       | I don't think I ever could do all the 25 so this is fine with me.
        
       | OisinMoran wrote:
       | Alright, I'm finally going to give it a shot this year!
        
       ___________________________________________________________________
       (page generated 2025-10-26 23:00 UTC)