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33325803 submissions, 1155804 registered users, 6999 public problems

Are you passionate about coding?

Try your luck in a brain challenge and join ADB Brain Wars contest!

ADB Brain Wars is a contest organized for Polish programmers.

Check the details at:

Win great prizes and have a lot of fun!

The elimination round begins on the 25th of March

Register today!

Innopolis Open 2018

Seven days left to register for the Innopolis Open - Olympiad in Informatics for high school students under 19 years old held by Innopolis University. The Olympiad has two stages: the online contest and the on-site competition.

Why participate?

  • It is a top-level contest - the problems on the Olympiad meet the level of the Russian Olympiad in Informatics. Contests are prepared under the guidance of the World Finals Champions of ACM ICPC.
  • Scholarship - winners of the second (on-site) stage will have an opportunity to be enrolled in Innopolis University without any admission tests.
  • Prizes – participants with the best results at the online contest will be invited to the final stage to Innopolis, the final stage winners will receive valuable prizes and souvenirs. Accommodation and meals are covered by the organizing committee.

To find out more about the Olympiad, please, visit our page:


The first stage (online contest) will be held on:

  • December 2, 15:00 (UTC +3),
  • December 17, 10:00 (UTC +3).

You may participate on both dates; the organizing committee will consider your best result. Registration is open until December 1, 2017. Participation is free of charge.

The second stage (on-site contest) will take place in Innopolis city on February 24-25, 2018.

Stay in touch

Innopolis Open 2018

Coding can give more fun than computer games – an interview with Ivan Katanić

After publishing an interview with Keshav Dhandhania we have decided to continue this project and present you other successful Spoj users, who can share their experience and all wisdom gained during their struggle with Spoj problems.

Today we present you Ivan Katanić a finalist in International Olympiad in Informatics a member of Croatian national team in computer contests and a long-time Spoj user with a #11th place in a world rank and almost 1000 solved problems.

Read more on our blog

Bubble Cup X

Microsoft Development Center Serbia is excited to announce the start of the 10th anniversary edition of Bubble Cup competition!

Bubble Cup is an international, ACM-style team contest aimed at university and high school students.

You can register now on Qualifications consist of two online rounds which start on the 1 st of April and on the 1 st of May and last for 25 days each. Both online rounds will feature several problems from the Sphere Online Judge. Ten best university teams and ten best high school teams will compete in the 5 hour long finals in Belgrade in September.

Teams can consist of high school pupils or students. Students must attend the same university. Complete rules can be found here.

There are going to be some great prizes awaiting the winners! More detailed information on prizes is coming on the website soon.

We wish you best of luck in competition! Let the coding begin!

Bubble Cup

Big languages update!

We are happy to announce that we have updated our languages database.

There are six new languages - one of them is a Swift which was on the top of your wishlist!

Please visit the article on our blog to learn more details!

From Spoj challenge to own startup. Short interview with Keshav Dhandhania

We would like to invite you to a completely new series of short interviews with successful Spoj users, we will talk about their projects and their first steps in the world of coding. If you think that you have your own story that can inspire others, write to us!

Here's our first interview with one of old Spoj users: Keshav Dhandhania, a co-founder at Compose Labs, a San Francisco-based company that has just released their first project Commonlounge (with a special community for Spoj users too!).

Read more on our blog.

Keshav Dhandhania photo

Innopolis Open

University Innopolis is organizing and holding Innopolis Open, an Olympiad in Informatics for secondary school students (until 19 y.o.). The Olympiad consists of two rounds — online contest and the on-site competition (held at Innopolis, Russia).

Winners of the first round will be invited to Innopolis to take part in the on-site competition. During the Olympiad, all participants will be offered a free of charge accommodation, meals and transfer from Kazan to Innopolis and back.

Winners of the second (on-site) round will receive awards and can be enrolled in Innopolis University without any admission tests.

  • The first (online contest) round will start on December 18 at 10.00 a.m. (UTC +3).
  • The second (on-site) round will take place on February 25-26 in Innopolis city, Russia.

Registration is open until December 15, 2016. Participation is free of charge. Please follow the link to register and find detailed information:

Innopolis Open

Registrations are now open for CodeChef SnackDown - a global programming contest | Qualifier starts on 27th May 2016!

CodeChef SnackDown is a multi-round computer programming contest, it will witness coders from schools, colleges, and organizations, across all ages, competing against each other on a global platform. This year there will be world's best 25 teams battling out with India's best 25 teams in Mumbai for the ultimate title of “SnackDown Champions” and hefty cash awards worth $22,500, a lucrative job offer with Directi, and plethora of cool SnackDown merchandises. The registrations are now open and the qualifying round will start on 27th May 2016. More information about the contest can be found here:


Passionate about algorithmic tasks? Take part in the eighth edition of international programming marathon Deadline24!

The teams of three may register up until February, 25. They will compete in the qualifying round online on February 28. For more information

Let the programming spirit flourish! becomes community partner in IndiaHacks is happy to become a Community Partner of Hacker Earth in their flagship event - IndiaHacks, the world's largest developer confluence, which aims to encourage programming and celebrate the spirit of coding among developers.
It comprises of a combination of online hackathons and programming contests. This massive event commenced on January 8th, 2016 with Fintech Hackathon and Bot Challenge programming contest - two of the nine technology tracks, scheduled for the month long code fest. The other tracks open for participation for developers are Algorithms, Machine Learning, IoT, Game development, Open Source, Online Commerce, Travel and Transportation. These hackathons will see developers build unique and interesting products in only 48 hours.

The top 20 teams/individuals from the online phase will be shortlisted from each track and will be invited to the offline conference, where they will again hack for 24 hours and present their ideas to a panel of judges. Developers also get to win some cool prizes like a Trip to San Francisco, Xbox One, Go Pro 4 and much more.

So if you are developer or a coder, register and participate in IndiaHacks ->

NASA and Freelancer’s Space Contest

Join the NASA Tournament Lab (NTL) and as they host a series of contests to crowdsource some of the most complex problems being faced by astronauts on the cutting edge of space exploration. Your contribution to these contests will be used in software simulations and by astronauts aboard the International Space Station!

For the first several contests, help build tools for the Robonaut R2, a robotic assistant used to help humans work and explore in space. Why not take this chance to be a part of humanity's journey to go beyond Earth's orbit and explore the vast wonder of space? Join the contests now.

Enter Coding Chill-out zone

International programming contest in the Mediterranean region.

Remote session : 26.06 - 03.07 2015
On-line session is OPEN for any registered users. Two categories: students & IT Pros. Join today and share our passion for coding. Code from your own #CodingChillout zone and rank high! Grab paid GitHub plans and Cloud computing tokens offered by Octawave.

Are you in Malta?
GOTO: On-site event in Malta on 11th July @Microsoft Innovation Center. All in relaxed and chilling climate of Maltese islands ... Just simply Enter Coding Chill-out zone, add song to the event playlist...and do what you LOVE. Register today:

CodeChef SnackDown 2015 - Code Your Heart Out

CodeChef SnackDown is a multi-round programming contest open to all. The multiple online rounds will culminate at an onsite grand finale, where 25 teams from across the India will be flown down to the CodeChef headquarters in Mumbai, India. For the participants residing outside India, there will be a parallel online round for the finale. While the Indian teams will compete for the cash rewards worth INR 6 Lakhs and a job opportunity with Directi, the global participants will have a chance to win exciting prizes like MacBook Pro, Drone Quadcopters, and Go Pro Cameras. So, register your teams now and strengthen your chances of winning.


We present the long-awaited new, fresh, and crispy design of SPOJ! It's taken us a while to get here since 2004, but hey, it looks good - doesn't it? There's now a new feature for tagging and grading problems. We are also working to make SPOJ as mobile-friendly as possible. Stay tuned, because there are many more surprises to come!

Goodbye Pyramid

During the last six months, we have been gradually migrating our "checkers" (servers which execute submissions) from old to new machines. The procedure required some care since the new machines have significantly greater processing power. The main difficulty was adjusting the time limits for problems: in general, the new machines seemed to be more "tolerant" of slow solutions than the old ones. Over the 10 years of existence of SPOJ, our great community has produced over 13.5 million submissions (10 million of which on the old checkers) and we didn't want to rejudge all of them. So, we designed an algorithm for recalculating submission running times by interpolation. Data for reliable interpolation came from a real rejudge of a representative sample of 5% of the submissions, i.e., 511,000 submissions have been rejudged over the past six months. At the end, we changed the time limits of test cases keeping them in relation to running times of solutions.

read more

Lambda Days 2015 Challange

For the second year in a row Lambda Days come to Kraków to bring together people passionate about functional programming. The tickets are out and the only way to attend at the moment is to get high score in their special programming contest. If you are interested in participation visit

Banning cheaters

We have intensified banning cheaters (users who copy codes from the internet and submit them here). Soon all of them from "Cheaters" thread on forum will be banned. If you are a cheater you can avoid ban by disqualifying all your cheating submissions until we get to you. After mentioned thread all users from top100 (and then top256) will be x-rayed.


Please check out a new contest CONSTANT. It's dedicated to problems in which you have to evaluate as many digits as possible of famous constants like π, e or φ.

Even if you are not interested, you may find there a link to the world records in this field. You may be surprised.

Do you teach algorithms, data structures or programming paradigms?

This is just a short message to remind you about SPOX which is dedicated for your academic activities.

Codecha (True Programmers' CAPTCHA) - the new project based on Sphere Engine - has just started.

Badges for SPOJ by Ricardo Bittencourt (ricbit)

Ricardo Bittencourt (ricbit) made SpojTweet to track your progress on SPOJ, and give badges for your achievements. Please have a look at an example page from the site, an exemplary tweet sent by a site, Ricardo's SPOJ forum post and more SPOJ tools.

Are you a novice in programming?

Please consider Simple Programming Problems. Comments and suggestions are very welcome here.

Programacion Competitiva Bolivia

A new subSPOJ for those who would like to try problems from Bolivian OI, ICPC and other contest. Please join

High School Programming League 2012/13 final results. The winner is Tomasz Rewak. Congratulations!

Top 5 contestants:

1 Tomasz Rewak II Liceum Ogólnokształcące im. Stanisława Wyspiańskiego w Legnicy, Poland
2 Mario Lipovsky Spojená škola Novohradská, Slovakia
3 Aleksandar Ogrizovic Gimnazija "Veljko Petrović", Serbia
4 Tomasz Zwornicki I Liceum Ogólnokształcące im. Tadeusza Kościuszki w Łomży, Poland
5 Wojciech Zieliński Zespół Szkół UMK: Gimnazjum i Liceum Akademickie, Poland

more ...

Top 3 Teams:

1 Gimnazija "Veljko Petrović", Serbia
   (Coach: Duško Obradović)
2 Zespół Szkół UMK: Gimnazjum i Liceum Akademickie, Poland
   (Coach: Anna Beata Kwiatkowska)
3 Zespół Szkół Techniczno - Informatycznych w Gliwicach, Poland
   (Coach: Daniel Kuśka)

more ...

ITRIX Online Programming Contest

ITRIX 2013 is a 5-hour ACM-ICPC style online programming competition organized by College Of Engineering Guindy, India. Contest starts 2013-02-27 16:30:00 SPOJ time. All college students are invited to participate.

SPOX Beta – the online grader for your programming courses

It is our pleasure to announce a new system dedicated to teaching programming. SPOX ( has been built upon the same engine as SPOJ, but dedicated to teaching in the context of private lessons or regular courses at different levels, starting from beginners to advanced university students.