Frequently asked questions

Here is a list of frequenlty asked questions. If you cannot find your answer here, you can contact us using this form.

Logging on the website

  • Why do I have to sign up on your website?

    Creating an account allows you to submit your programs to the automatic testing tool, see solutions, get help, and access more tasks and courses.

  • I cannot sign up or log in. What should I do?

    You can sign up from the login box on the left of the page. If the link does not work for you, or you cannot log in after you signed up, contact "info @" and explain your problem.

  • I forgot my username or my password. How can I recover them?

    Go on this page.

  • Can I change my username?

    No, there is no way to change your username in the current version of the website.

Tasks and corrections

  • I have no idea on how to solve some task. Can I have the correction?

    The correction of each task is only accessible once you have solved it, because we do our best to help you solve tasks by yourself, and make you improve better.

    You can get advice in the “Advice” tab of any problem, automatically, or asking help to users having already solved the task, who will then be able to assist you.

  • My program looks right to me but I get an error when I submit it. What should I do?

    The manual of the online judge may help you understand the problem. If not, ask for help in the “Advice” tab: other users will be able to help you.

  • I am looking for the solution of an algorithmics problem for my school. Can you help me?

    No. The goal of our website is not to directly help you do your homework. However, training on our website, you will learn how to solve your problem. In the meantime, you may seek help on forums like those on OpenClassrooms or Zeste de Savoir.

Contests and olympiads

  • I would like to take part in the olympiads, what should I do?

    You must be a French resident, enrolled in a school but before the baccalauréat, be less than 19 years old, and train enough! For details, read the page selection of the French team.

  • When is the next France-IOI contest?

    When we will have time to organize it! In general, contests are annouced between 4 and 6 weeks in advance, on our website. Some other contests occur on a regular basis. USACO tasks are translated by France-ioi (look here for more info).

Learning computer science

  • Where can I find courses on other programming languages?

    Programming languages usually have a main website in English with guides or tutorials. You may also look on OpenClassrooms and Zeste de Savoir.

  • I am looking for pseudo-code or programs for classical algorithms. Where can I find them?

    We give pseudo-codes and codes only once you have solved the tasks. In addition to learn knowledge, you will learn how to master methods to solve more complex algorithmics tasks by yourself.

  • I would like to buy a book on algorithmics. What can you suggest me?

    We consider that reading the description of an algorithm in a book, without having tried to solve the underlying problem by yourself, is a wasted occasion to learn and improve. In algorithmics, knowing algorithms is less important than learning how to discover them by yourself. A training website like ours is the most effective way to improve.

    Books remain useful to have different point of view on algorithms you discovered on our website, or to find algorithms we do not have yet. We suggest two books:

    • Algorithms in language C, by Robert Sedgewick. A very accessible book covering many algorithms. It contains an implementation in C of every algorithm presented.
    • Introduction to algorithmics, by Thomas Corman & al. A very complete book, mainly on theoretical aspects and containing many interesting problems. It might however be a bit hard for beginners, and only a pseudo-code is given for each algorithm, not always easily translatable to a programming language.

    Here is also a list of English books on the topic.

  • I would like to become a computer scientist. Can you help me?

    Training on our website will certainly help you work in the field of computer science. Indeed, mastering algorithmics and techniques to write programs with no bugs are more than useful when developing any kind of software.