Project Euler - Hacker News

Posted by swatson741 11/12/2025

566 points | 134 commentspage 2

meken 11/12/2025|

One of my best memories was in undergrad there was one semester in 2013 where half a dozen of my CS classmates and I competed to try and solve the most Project Euler problems. We had a leaderboard and everything.

I saw first hand how much faster my friend’s Java solutions were than my Python solutions.

Good times.

kekqqq 11/12/2025||

No one tells you that they delete inactive accounts. I used to have over 300 solved problems htere. Now it is all gone, all the effort, but the skill remained of course.

inasio 11/12/2025||

A few years back (10 maybe?) they had a disk crash, and there was a notice that for people with 100 or more problems solved they'd do an extra effort to recover their solutions and add you back, not sure if it was only posted on the main website. I was lucky to get my account back at the time

kekqqq 11/13/2025||

Ah okay, I was active there 9-12 years ago, so it migh been before the crash. I remember checking it, however, 7 years ago, and I was still able to log in.

doodpants 11/12/2025|||

So, I gather that you treated your solutions as throw-away code, rather than keeping them? Kind of surprising, considering that some problems build off of each other, or otherwise benefit from sharing code; you never know when the code for one solution could be useful later. For example, a prime number generator/tester is necessary for many of the problems.

(I have all my solution code, in source control no less, so if I ever lost my account, I could just run them all and re-enter the solutions.)

kekqqq 11/13/2025||

> So, I gather that you treated your solutions as throw-away code, rather than keeping them?

I kept the code that I found clever or useful, but I had a very borderline approach to archiving my stuff in general back then. I was still in high school.

yogsototh 11/12/2025|||

I remember there were data loss, but my account appears to have been recovered. You may try to login again, and with luck, like me you will get back your history.

cgh 11/13/2025|||

I still have the code for the first 50 problems in GitHub. The last commit was thirteen years ago. I don’t know why I checked these in rather than treating them as throwaway code like I did for so many other things, but I’m glad I did as I’m sure my PE account is gone now too.

Loocid 11/13/2025|||

How long before they start deleting? I haven't logged in for 5 years and my account is still there.

mrgoldenbrown 11/13/2025||

YMMV - I just tried to log in and after a few failed password attempts was able to use my account recovery code from 2014 and get in.

akudha 11/12/2025||

Are there other similar sites? I remember this one, for bioinformatics

https://rosalind.info/problems/list-view/

mrgoldenbrown 11/13/2025|

I like Advent of Code. Pretty popular, and more general purpose programming puzzles rather than euler, which tends to be pure math focused.

https://adventofcode.com/

nik9000 11/12/2025||

I ranked on that once! I was like the 23rd person to do one of the new problems one time. Just about as low as you can rank. It was a fun puzzle but you had to be awake at a funky time to do it.

ketanmaheshwari 11/12/2025||

I solved a few using AWK, fun: https://github.com/ketancmaheshwari/projecteuler

n4r9 11/13/2025||

After learning AWK I realised it could be used really neatly for problem 67. I remember it was blazing fast, orders of magnitude faster than Python

mjcohen 11/13/2025||

Did you use the regular version or the one with multiple-precision values?

ketanmaheshwari 11/13/2025||

I used the regular version. Actually, I don't even know what is multiple-precision values -- will look it up.

Sparkle-san 11/12/2025||

Like many others here, Project Euler was foundational in my education and growth as a programmer.

Leonhard Euler himself is an incredible figure and arguably the most prodigious contributor to mathematics throughout history. So much so that people started naming things discovered by him after the next person to have proved them.

https://en.wikipedia.org/wiki/List_of_topics_named_after_Leo...

zelphirkalt 11/13/2025|

Maybe Gauß takes that trophy. To me it felt in mathematics lectures, that Gauß had his hand in everything. Euler might have had that too, but I am not that aware maybe.

bre1010 11/12/2025||

I discovered project euler as a novice programmer in high school around 15 years ago. I loved how solving a problem unlocks a secret forum only available to other solvers. I would spend hours reading through everyone's prior solutions and trying to understand them. One guy had tagged his profile as "haskell" but would always provide his solutions in ruby which threw child-me for quite a loop (I actually thought ruby and haskell were the same language for some time)!

matthewaveryusa 11/12/2025||

I attribute project euler for instilling the playful enjoyment of writing programs in college while I was studying electrical and computer engineering. I owe my career to it!

codexb 11/12/2025|

Wow, I can't believe this is still around! I'm glad to see artifacts from the past like this are still out there on the internet.

Makes me miss Google CodeJam though.

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