Problem that has been solved by the smallest number of people (31): http://projecteuler.net/problem=453
Any hints? Anyone?
Project Euler
51–60 of 138 posts
Re: Project Euler
#52I solved about 80 of them, then my interest waned a little. But I wonder, are there any hints or recommended reading for the harder ones? Some of them I have no idea how to even start working on..
> Some of them I have no idea how to even start working on Do you have an example of such a problem?
I am sorry, it's like 5 years back when I did it, and I don't remember (nor I am inclined in pursuing it further). (I didn't gave up because it became impossible, I just became less interested.)
But lot of those harder ones - as far as I can tell - required pretty deep knowledge of number theory, which even though I studied math (10 years ago), didn't have. I think it would be nice if there was sometimes a hint about what the people should study to be able to solve it.
Re: Project Euler
#53Earlier quoted context omitted.
What company was that? Sound like a great place to work!
Mixrank, they're a YC company. Nice folks and really sharp too.
Cool. I'm looking right now. Mind sending me an email so I can ask you some more questions offline about Mixrank? It's in my profile.
Re: Project Euler
#54I always liked this set of challenges/riddles, though it is directed at Python specifically. I appreciated that it forced you to deal with some Internet-related programming tools and concepts.
Re: Project Euler
#55Weird, I was just talking about this earlier when someone asked for productive activity on train journeys to/from work.
I used to do these problems years ago when I was still a student and later when commuting to London. I did as many as I could on paper before trying to program solutions. I'll have to log in sometime and finish the few I missed.
Re: Project Euler
#56The best technical interview I ever had involved picking a random Project Euler problem in the hundreds and pair-programming our way through it. The CTO wrote his version in Python and I worked in Perl . . . he was astounded mine ran 8x faster. The same company also had regular hack night where everyone drinks a lot of Tecate, agress on a Project Euler problem and a language no one knows, and races. Fun times.
That sounds like a really fun place to work.
Re: Project Euler
#57To be honest, I'm shocked this is on the front page as this website has been out for years and already notably mentioned, but I guess it's good to recycle very important websites for those who haven't heard of it. My favorite problems is 98. This problem, along with the Sudoku one at 96, require much more careful programming than some of the others due the drastically fewer number of people who solved it compared to…
You may have inadvertently reversed the arrow of causality there :)
Re: Project Euler
#58I love project euler, but I've come to the realization that its purpose is to beat programmers soundly about the head and neck with a big math stick. At work last week, we were working on project euler at lunch, and had the one CS PhD in our midst not jumped up and explained the chinese remainder theorem to us, we wouldn't have had a chance.
I feel the same way. It was presented to me as a great way to learn new programming languages. But really it's challenging your ability to design algorithms, and overwhelmingly mathematics-related algorithms. (I'm not saying the site itself claims anything different). It doesn't heavily challenge you to advance past a most basic level of a programming language. For example, most Project Euler problems are solved in J…
"most efficiently"
Stop doing that and its a lot more fun. It annoys me when a PE problem is specifically designed to make it impossible if you do it the "wrong" way. Most PE problems allow crazy solution strategies. The bad ones only have the one true way that is computationally feasible.
A few posts up someone liked problem 267. I would pick random numbers, run them, then keep the winner and make n-1 new random numbers for round 2 and keep running rounds of multiple threads until bored, remembering the best result so far. Yes, that is not a very smart way to solve the problem, but its a very fun way to exercise the heck out of your knowledge of threads in some new language. Or you could make an insane thousand thread pipeline and hope for convergence. Or a thousand processes on a parallel cluster pipelined together. Could I write my random processor using BASH to baby sit a bunch of octave instances? Newtons method at least at first glance would be too easy. Could I solve it graphically, literally, by graphing some results and doing image manipulation and analysis of the generated graphic file to obtain the numerical result and feeding back for more "zoom" detail? Totally ridiculous unless the whole point is some weird computer vision project. Given an emulator for a IBM1620 mini-mainframe from the 60s, could I write a perl script that output random Fortran-II test runs for the emulated mini-mainframe to compile and process and then another perl script to eat the virtual "printer" output of the mini-mainframe to get random run results? Problem 267 looks like a fun one to solve the wrong way.
This is the unfortunate part of PE becoming popular at interviews. First of all it surely has nothing remotely to do with almost all programming jobs, secondly, "having fun while doing crazy things" is probably not the ideal IT department mission statement or employee selection criteria (although it would explain some things I've seen over the years...)
The proper tool for 99% or so of PE problems isn't a programming language anyway, its octave/mathematica/parigp. So its not too far out of the spirit to try crazy stuff.
Re: Project Euler
#59Project Euler is great. Another one, but more algorithm and CS oriented: hackerrank.com
Hackerrank is great. Thanks for sharing!
Re: Project Euler
#60Earlier quoted context omitted.
When I was conducting quantitative interviews I ended up doing the same thing. One of my favorite problems to give was 267 ( http://projecteuler.net/problem=267 ). It has a few "aha" moments but also requires coding to get it done.
As a finance person I really like this one. I'll have to check it out when I get home from work. Thanks!
Glad to help! If you run into any trouble let me know (email in profile) and I'll provide some hints.