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ICPC 2025 World Finals Results
- barishnamazov 1y agoI was onsite today watching the contest live, and great atmosphere all around. One surprising outcome: the team in 17th place solved the same number of problems as the team that won gold in 4th place. Hopefully that isn't too demotivating to any team and we can see better separation in the future. After all, it can only mean that the problemsetters underestimated the contestants ;) Congratulations to all the teams!
- tshaddox 1y ago> the problemsetters underestimated the contestants Except for problem C, which was only submitted by 4 teams, all unsuccessfully.
- cperciva 1y agoI don't blame them. That problem statement seems to be deliberately confusing.
- hatthew 1y agoI doesn't seem that unclear to me? I absolutely don't have the skill to solve it, but it took <2 minutes to understand the problem and goal.
- orlp 1y agoIt doesn't seem that hard to solve to me either. It's solvable with basic linear programming. 1. Add a variable for each node, and a variable for each output edge from stations. 2. For each reservoir add equality constraints to the sum of incoming edges with the coefficients given in the problem. 3. For each station add equality constraints between the weighted sum of its inputs (which is 1 for the root station) and its outputs (which are the variables we added). 4. Add an out_edge >= 0 constraint for each output edge on stations to forbid illegal negative flows. 5. Add a variable m which is constrained to be less than all the output station variables. 6. Maximize m.
- amluto 1y agoReplying again, having actually read the problem more carefully: the problem isn’t that simple. There will be a few tens of thousands of variables. The LP is extremely sparse, and I’m sure a good solver could solve it within the time limit, but a little team-notebook-sized dense solver would take at least a few trillion operations to finish and would not be nearly fast enough.
- orlp 1y agoAs I mentioned in my other comment: > I'd just like to clarify that I'm not saying this is necessarily the solution the problem writers were looking for, or that it will run within the allocated time. Just that it's a feasible solution. I don't doubt there's a clever dedicated flow algorithm the problem writers intended instead of the blunt tool which is LP.
- jeremykvlim 1y agoI solved C using LP. You may attempt to submit a solution here if you want to try: https://open.kattis.com/problems/brideofpipestream https://open.kattis.com/problems/brideofpipestream You may view (one of) the judge's solution to this problem (and the rest of the problems) here: https://github.com/SnapDragon64/ACMFinalsSolutions/blob/master/finals2025/brideofpipestreamDK.cc https://github.com/SnapDragon64/ACMFinalsSolutions/blob/mast...
- amluto 1y agoThis happens every now and then. Basic LP isn’t conceptually so bad, but the ICPC environment doesn’t come with CPLEX or Gurobi, let alone a less fancy open source tool. And there is definitely not a copy of cvxopt around to make this easy. Even if you want to quickly kludge up an interior point solver, you don’t have a linear algebra package available (sorry, no numpy or BLAS). What you can do is to submit a 25 page PDF that the organizers will print and stick on your desk for the competition. And you could put a careful implementation of a very basic simplex solver using dense matrices that is optimized for ease of transcription, taking up, say, half a page. You would hope not to use it because it’s absurd, but then if this problem C shows up, the fastest typist on the team can type it in verbatim. If I, personally, did this and won the contest as a result, I would feel slightly bad. In my opinion, the contest organizers should either provide an LP solver or refrain from giving obvious LP problems like this. Obviously OpenAI could kick everyone’s butt by typing faster than any human and by effectively having a large memorized library of pre-written code. Honestly, LLMs vs humans in the ICPC feels a bit like IBM’s old Jeopardy stunt where the machine had a huge advantage in its ability to push the button.
- tshaddox 1y agoYes, I meant to imply that the problemsetters are to blame.
- pykello 1y agoVideo recordings: https://www.youtube.com/playlist?list=PLaSPkFE9cpGT_SuxamW9ejNESR6ia3nXs https://www.youtube.com/playlist?list=PLaSPkFE9cpGT_SuxamW9e...
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- imadethis 1y agoThe headers A-L are links to the problem PDFs if you want to see.
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- 512 1y agoThe "Diamond Sponsors" of the event are Huawei and OpenAI. I found the welcome note from OpenAI [1] quite curious: "[...] Eventually, AI will be able to solve even the hardest contest problems that we’ve seen yet. It will work alongside us and help drive the discovery of new knowledge. What you take from this week - the sense of being stuck, the thrill of progress, and the practice of building together - will remain critical as you shape your community and the future you build. [...]" By Chief Scientist of OpenAI, Jakub Pachocki. Who happens to be an incredibly accomplished Competitive Programmer (2nd in ICPC World Finals, Winner of Code Jam, 2nd in Hacker Cup). [1] https://icpc.global/community/history/brochures/world-finals-2025-brochure.pdf https://icpc.global/community/history/brochures/world-finals...
- goalieca 1y agoThat curious statement comes across as inappropriate. These talented students are among the best in the world. Yet, openai chose to make it about and praise themselves. That was not classy.
- foxglacier 1y agoSurely it's meant to reassure the contestants that they're not wasting their time. They'll obviously know AI can do some of this stuff so it's a reminder that the true purpose of the competition isn't to be good at programming. People still compete in playing musical instruments, riding horses, painting pictures, etc. All redundant because of technology but still they do it for other reasons, not the practical utility of the product of their work.
- lordhumphrey 1y agoPeak HN here. Playing musical instruments is "redundant because of technology". And so is "riding horses"? And "painting pictures". Eh, what?
- foxglacier 1y agoFor example, almost all music listened to today is recorded, not live. It was the opposite way around 100+ years ago. Almost all portraits are photographs, not paintings, etc. The common practical uses of those skills are gone and they're relegated to small niches, luxury services, and personal pleasure.
- cptroot 1y agoDoes anyone know how long it will be until the input/output data packet is made available? I'm interested in taking a crack at some of these but know I always miss an edge case.
- jeremykvlim 1y agoIt has been made available here: https://open.kattis.com/problem-sources/ICPC%20World%20Finals%202025 https://open.kattis.com/problem-sources/ICPC%20World%20Final... It does seem to be missing 3 problems though.
- rfoo 1y agoYou can try your solutions here: https://wf25open.kattis.com/contests/wf25open https://wf25open.kattis.com/contests/wf25open I believe it runs with the same test data as in the actual contest.
- dooglius 1y ago> You need to join the contest in order to be allowed to submit. Doesn't seem to be publicly accessible to non-participants (yet?)
- akamaka 1y agoIn the TV show Silicon Valley, there’s a joke that Nelson “Big Head” Bighetti, the perennial underperformer, did his undergrad at ASU. But I guess that’s one thing the show got wrong, because Arizona State University finished among the top three American schools in the world finals.
- riku_iki 1y agoI expected fast response from AI labs about what kind of medals top models could win.
- coolThingsFirst 1y agoGreat memories of ICPC. Their problem statements are so creative it’s insane. Nothing like CF garbage, solving imaginary patterns that no one cares about.
- osti 1y agoWhat do you mean by imaginary patterns from Codeforces?
- coolThingsFirst 1y agoThe problems are really low quality. Topcoder/ICPC/CodeJam have the best problem statements. Check out this for example: https://codeforces.com/contest/2136/problem/C https://codeforces.com/contest/2136/problem/C Why would I care if some array can be obtained by combining some other patterns?
- pxx 1y agoThis is a pretty neat problem. Maybe this isn't the activity for you...
- coolThingsFirst 1y agoNo, sorry. You have a bad taste.
- jmpman 1y agoWow ASU, the 4th highest US School. Not bad when also being a top party school.
- pedrosorio 1y agoYou can check all the teams and their members here: https://cphof.org/advanced/icpc/2025 https://cphof.org/advanced/icpc/2025 It's rarely the case that looking at school names is useful (for many things in life) when there are more data points. In this case, without any insider knowledge, just by looking at their profiles, the relevant name would appear to be Benjamin Jeter (https://codeforces.com/profile/BenjaminJ https://codeforces.com/profile/BenjaminJ) rather than ASU. Currently 5th active American in the top competitive programming platform, top 200 worldwide (https://codeforces.com/ratings/country/United%20States https://codeforces.com/ratings/country/United%20States). That's elite. In teams of 3, even one "super player" can make a big difference. Almost certainly carrying that team.
- sanatik 1y agoMy alma-mater is only 61st. I remember the times we’re top 30. Great atmosphere though! I wonder if these competitions will become obsolete as LLMs advance.
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- MisterSandman 1y agoI don’t see why it would. Chess is still bigger than ever.
- agnishom 1y agoWhat is Moscow's secret to training their programmers so well?
- pedrosorio 1y ago*St. Petersburg I guess, like a lot of other sports at the college level, having a reputation that attracts the best competitive programmers (and a great coach to go along with it) doesn't hurt: https://en.wikipedia.org/wiki/Andrey_Stankevich https://en.wikipedia.org/wiki/Andrey_Stankevich
- userbinator 1y agoThe "Russian hacker" stereotype is not at all fiction. If you've ever worked with developers from any of the former USSR, you'll know what I mean; they are not afraid to be creative and do whatever it takes to solve the problem.
- dikei 1y agoStart training them from a very young age: competitive coders typical start in secondary/high school or even earlier. Russia has specialized schools to support this kind of education, so are China and many other countries. Thus, they rank very high in IOI and ICPC contests
- partomniscient 1y agoThe ICFP progamming contest for this years International Conference on Functional Programming started today if anyone's interested. https://icfpcontest2025.github.io/index.html https://icfpcontest2025.github.io/index.html
- wiz21c 1y agowhat's the meaning of of the A,B,C... columns It's a ratio but of what over what ?
- concacinquant 1y agoA, B, C... are the ID of the problems (not sorted by difficulty, teams have to figure out the order). For each cell of (team, problem), the "ratio" x/y isn't actually a ratio. x means how many submissions were made. y is the minute when the accepted solution was submitted. For example, "3/298" means they made 3 submissions in total, and the accepted solution was submitted in the 298th minute (the contest lasted 300 minutes). The penalty ("Time" column) is calculated as (sum of y) + 20 * (sum of (x-1)).
- acomjean 1y agoThe columns are the questions. The score is “total att/solved”, (attempted/ solved?) though that doesn’t help much. I’m guessing you need to get the answer within the time limit. https://worldfinals.icpc.global/scoreboard/2025/problems/A.pdf https://worldfinals.icpc.global/scoreboard/2025/problems/A.p...
- saagarjha 1y agoThey're the problems with how many teams correctly solved it over the number of teams that attempted to solve it.
- lordhumphrey 1y agoWow, China with a pretty dominant position there with 3 teams in the top five. Interesting seeing Karlsruhe there too, I'd been looking at that school.
- concacinquant 1y agoThey have won the championship multiple times actually. There are times where "Western teams" are just full of mainland Chinese communicating in Mandarin (e.g. a few MIT teams in the past including the 2021 champions...)
- lordhumphrey 1y agoWowser. Is it a similar story to the Chinese olympics successes - train kids from a (very) young age in specialised schools?
- muldvarp 1y agoI expect OpenAI to have crushed the competition here.