Project Euler

I have done Project Euler very sporadically since high school. To date I've only done problems 1-54. Despite this, I think the website was a big contributor to my love of programming. I found it before knowing about leetcode and I think it prepared me well. I think I owe Project Euler a decent %-age of my eventual entry into Software Engineering as a field.

This website was a part of my education as a computer scientist and seeing it here again I'm curious for the full story of how this site was made. Who made it, what do they do now, is it part of a broader project they have?

There is only very basic info here: https://en.wikipedia.org/wiki/Project_Euler

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...

Glanced at the exercises. It appears that two of them have numbers arranged in a triangle and ask for a longest path.

Hmm. Given such a triangle, let m be the largest number in the triangle. For each x in the triangle, replace it with m - x. For the resulting triangle, solve it to give the shortest path using one of the well known network shortest path algorithms.

A great one of my favorite websites of the past. Wonder how they are coping with the issue of their users using AI to solve problems.

The most fun on this site is solving a problem and then having your mind blown by solutions in Apl/j/k and trying to guess what they mean without knowing anything about those languages

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

i was a euler fanatic some years ago reaching problems in the 500s albeit, skipping problems along the way. at that point, too many problems required a deeper math background than i possessed so i abandoned it. what amazed me was that others composed solutions that solved problems in mere milliseconds that brute force approaches would still be running when the universe cooled to absolute zero.

I love running euler problems when trying to learn the basics of a new programming language. I have a small collection of programs in like 10 different languages that I keep around as a reference for things because I always try to use language-specific features to solve the problems, and then I reference them as examples.

Ha! I did a lot of these around 2007-2008. I solved the first 100 or so ones. Solving these were more fun than any other programming problems site I've seen. I quit it when I realized I was spending 4+ hours per problem - I couldn't justify the time.

Beyond a certain point, most required some knowledge of elementary number theory.

this is how you end up getting into APL/array langs for sure.

I wrote Problem 619 (https://projecteuler.net/problem=619) which was published on 2018-01-27 and solved by 474.

The problem was based on 2013 Putnam Exam problem A2 (https://kskedlaya.org/putnam-archive/2013.pdf) which I took at the end of undergrad.

I got an email six years later (in November 2024) telling me they accepted the problem:

Greetings!

Please excuse the email. It's quite possible that you are no longer active at Project Euler, but we are currently trying to retrospectively acknowledge contributors of problems.

You were identified as being involved with Square subsets [619 m] in Sep-17.

If you would like to be added as a verified contributor, please reply to this email and provide the username you currently use at projecteuler.net. Please note that contributor usernames will not appear publicly, rather they will be used internally to unlock new contributor awards we are introducing.

Regards,

Project Euler Team

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.

very surprised this project is still releasing problems weekly - I remember this being up when I was in high school. maybe I'll pick it up again since I only did the first ~30 or so back then.

So much more fun than leetcode. OTOH, unlikely to help you in an interview.

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

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

I think a hat-tip is due to freeCodeCamp for introducing Project Euler (along with Rosetta Code) to a new generation of programmers:

https://www.freecodecamp.org/learn/project-euler/#project-eu...

I wrote Problem 371, https://projecteuler.net/problem=371 , as a high school student in 2012!

I'm so happy to have spent twenty years of my life learning math and solving problems on Project Euler and elsewhere.

What's really neat is that most of the problems are so compact that you can just read about the full problem, then spend hours and days thinking about possible solutions.

I created a PDF version that I keep on my Remarkable for puzzling: https://github.com/pveierland/project_euler_offline

There is a somewhat similar idea behind "Ponder This" by IBM https://research.ibm.com/haifa/ponderthis/index.shtml They post a problem every month and in the end post a solution. I used to spend a bit too much time on those.

So, to remind myself, Euler's name is pronounced more like Oiler, right?

After opened https://projecteuler.net/ I got

403 Forbidden Request forbidden by administrative rules.

Note: I didn't know and open this website until now.

Since this is still on HN frontpage. Does anyone suggest any math books to help solve these problems. I am pretty sure you can't solve problems above 50 without strong maths background.

12 years ago I was a failed computer science student, wasting my time on drugs. Having failed so many classes I did not see any future at all, and I was considering killing myself to get out of the anxiety and stress. My confidence regarding programming etc was 0.

I decided to apply for a junior developer job. I got an interview and to prepare for an interview I found this site, Project Euler. I did ten or so tasks.

The interview started out pretty bad, they asked me some technical questions which I did not give good answers to, and I saw that they where not impressed. Then they wanted me to solve two programming problems on a white board. Imagine the relief I felt when both of these questions where from the ones that I solved on Project Euler a couple of days before! I nailed them and the interviewers where clearly impressed. In the end they hired me and motivated it with that although I lack a lot of theory I am obviously a very good coder haha.

Anyway, that was what I needed, when I got this job I quit the drugs and got my act together. 12 years later I live a confortable life as a freelancer and have even managed to build my own SaaS with paying customers! Thank you Project Euler.

Whelp, the opening “problem zero” stuffed me up.

> A number is a perfect square, or a square number, if it is the square of a positive integer. For example, is a square number because ; it is also an odd square. The first 5 square numbers are: , and the sum of the odd squares is . Among the first 881 thousand square numbers, what is the sum of all the odd squares?

I wanted to use Uiua, and hence:

/+ⁿ2+1⍜÷⇡ 2 881000

But Uiua doesn’t support big ints, just f64. So yuck, python to get an accurate answer. Just sad now.

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)!

How I learnt about prime number sieves.

Good prep for Advent of Code in 2 weeks.

I learned so much from this site- including that so much education comes from being prompted to ask the right questions.

2007 I remember writing one-liner ruby solutions up to 100.

I was trying to create an account but it kept saying the confirmation code was wrong. Idk if that's a bug but... I was using the audio captcha. Still, the website seems pretty neat!

Thanks for reminding me this; I'd try to solve them both in Scheme (s9fes) and JimTCL.

During my university time, I used to do a lot of different programming puzzles and algo. I think it an invaluable training that every serious engineer should try without relaying on AI.

Skills are trained by practice and thinking. Skilled people will never be subsidized by AI. Unskilled juniors, who don't train properly will go into tranches (as it's already happening).

The leetcode before leetcode. Hail.

Project Euler spurred my love for math and programming when I was 15. I got through the first few with pencil and paper and then quickly realized I was going to need to learn how to program. Got started with Java (in Eclipse) and then moved on to Python. I feel like it completely changed the trajectory of my life.

Thousand of hours on this. Love it.

I did a lot of these when I was around 15-16 and it solidified for me my interest in CS but in general abstract thinking and problem solving. Great site.

These are both a lot more fun, and a lot more educational than leetcode problems. Strongly recommend for anyone looking for practice problems when learning a new language or whatever.

Hackerrank also used to host(still has?) PE problems with additional test cases.

I love a good puzzle solving club. Some of my favorites: https://www.themastertheorem.com/ https://en.wikipedia.org/wiki/Perplex_City https://en.wikipedia.org/wiki/MindTrap

Anyone else having problems registering? or is my solution to Problem Zero wrong...

I thank project Euler because whenever I face some coding challenge that has any mathematical inclination, I will(!) impress interviewers. I spent a lot of time on it, and learned a considerable amount of theory and hacks. What a privilege to be able to do this, instead of digging the fields and other manual labor. Thanks culture!

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.

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!

This is such a great site.

I remember visiting Project Euler back in 2013/14 or so. Was really my first introduction to programming exercises as youngin. Probably did fifteen or so of them before ADHD kicked in though. A small gem on the web.

Project Euler was what I used to get comfortable with my two main languages -- first python and then rust.

I loved to solve it and then look through all the different solutions and find pretty ideas and idioms.

I too owe had my love for programming captured through project Euler. I am immensely grateful to my maths prof who introduced me to it.

I also love looking back at my old PE code and having absolutely no idea what it doing. No comments, no docs, no notes. From a different era.

I remember it vaguely but there used to be a badge awarded for being among the first 100 people to solve the problem. I was obsessed with getting that badge to the point that I spent obscene amount of time solving the-then recently released problem even when the following day was my final exams. I did manage to get that badge though. This was circa 2013. Fun times!

Anyone else having problems registering or is my solution wrong?

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.

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.

fake frustration yet another thing named after euler.