Project Euler Forum

The fist solver only use 13 minutes and 50 seconds to solve Problem #930.

The remarkable thing is that he beats hos-lyrics,abcdefg3085, and BerkeleyMath these fast guys. This is the first time for him to take a Gold Medal and most of all, after 1 hour, while I am writing this topic, there is even no 2nd solver.

According to clist.by
His best rank in the recent 30 problems is only rank 11(Problem #918), the average is 40~50.
https://clist.by/account/vapor/resourc ... euler.net/

Can I suspect something?

(1). Use one account to propose a problem and use another account to solve it, so that it is easy to take a Gold Medal.

(2). Simulate many problems that ProjectEuler may publish and luckily guess one problem.

(3). Third? Come on!!! There are no third probability!!!

Can you tell me who proposes Problem #930 ?

I think that is far from decisive evidence for cheating. A likely reason is that this (or a similar) problem might have already appeared somewhere (that's how Min_25 solved 551 in 1 minute) or they might have came up with the same/similar problem on their own beforehand. Or, maybe they might have just had a brilliant idea very quick, that's also possible (there is an old problem for which top solver took 3 hours, which seemed just trivial to me and I solved it in 10-15 minutes and it was not one of these unfortunate cases where the supposed correct answer was wrong)

Swistakk wrote: Sun Feb 02, 2025 11:34 pm I think that is far from decisive evidence for cheating. A likely reason is that this (or a similar) problem might have already appeared somewhere (that's how Min_25 solved 551 in 1 minute)

If you are talking about Min_25. Do you know how fast min_25 is?
According to old records
http://euler-crawler.appspot.com/search/Min_25
Min_25 has 47 times Rank#1, 86 times in Top 3.

Most of all, If this problem has already appeared somewhere, It is not possible to be seen by only one person. For example, Problem#917, the first three guys are too fast, 5 minutes, 6 minutes, and 7 minutes, But the 4th solver took 18 minutes to finish it because this is a problem which already appeared somewhere. So the top three solvers may have already seen this problem before.

I insist my suspicion is reasonable. Let's see how freaky the record is:

1st vapor only took 13 minutes to finish it.
2nd hos-lyric: 1 hour 59 minutes.
3rd abcdefg3085: 2 hours 8 minutes
4th universalset: 3 hours 7 minutes
5th montyn: 4 hours 56 minutes.

I think the fact is that vapor use another account to propose this problem. He cannot finish it too fast(like Min_25's 1 minutes), otherwise people may ask:"Has this problem already appeared somewhere?", Actually this problem didn't appear before.

He cannot also finish it too late, otherwise he may miss the gold medal because the are many fast guys competing the first place.

But Finally he underestimated the difficulty of this problem and left the freaky record, a "too-fast" 1st finishing time.

The proposer of this problem is well known and already has earned the Gold Medal some time ago. The member you have suspicions about is a veteran solver who has been around almost a decade and has an outstandingly successful, well-paced solve rate.

On another note, echid, could you please send me a PM with your current Project Euler username so that I can update your username here.

I solved it myself just now, and I agree with euler. I've seen vapor's name around for almost a decade myself as well. The timing is not suspicious. The problem is extremely difficult, but if you have a lot of experience in certain topics (to be vague) and very very good intuition, I very much believe that a full solution can be coded in that amount of time. I'm guessing that the stars just aligned for vapor here and every necessary idea was familiar.

If You say so, All I can do is accept it currently.

But there are still too many possibilities. I will find the fact by myself.

I insist on my point of view, The 1st finish time is freaky and unreasonable, especially the other competitors are monsters with fast speed.

If vapor were a fast guy, I would not say anything. But he is only fast in this problem, slow in other problems. Don't you think it is weird?

By the way, veteran solver doesn't mean much to me. Only 17 problems whose answers are currently absent in Unlucky's answer list. Just solve 17 problems to be a veteran solver. It doesn't impress me much, not a great achievement.

echip wrote: Mon Feb 03, 2025 10:44 am By the way, veteran solver doesn't mean much to me. Only 17 problems whose answers are currently absent in Unlucky's answer list. Just solve 17 problems to be a veteran solver.

That's not what "veteran" means. Multiple people have just told you that the user had solved many problems before any idiots started posting public answer lists.

I think the problem gives way too much advantage to users that have access to float128, as it can be solved with an inefficient algorithm that requires less specialised technical knowledge of a particular topic. It wouldn't matter if it weren't for the leaderboard, which makes me a bit salty that I could have achieved a higher ranking otherwise, although I will get over it.

Unfortunately I had literally zero knowledge of the special topic needed to solve the problem properly

Times like these where I wish there was a hint option

UPDATE: actually there's ways around the precision issue pointed out in the thread, now my solution only takes 63s