About

algos.sh is a free place to learn algorithms and practise for coding interviews: illustrated guides you can step through on your own input, 671 practice problems with a code runner for Python, C++ and Java, 788 quiz questions, mock assessments, and a progress page that points out your weak spots.

How it was made

algos.sh was built with an AI assistant. That includes the site's code, the written guides, the interactive graphics, the problem statements, the tests and the reference solutions. A person directs the work, decides what goes on the site and tries it out, but most of the words and code you see were written by the assistant.

We'd rather say that plainly than let you assume otherwise. It also explains how the site is checked: instead of trusting that something looks right, it is run.

• Every problem's reference solution is compiled and run against its full test suite in each language it supports, and the starter code is checked to fail.
• The code shown in each guide is compiled and tested in Python, C++ and Java the same way.
• The graphics have automated tests that step through each algorithm and compare the result with the real answer.

Tests catch wrong code, not every unclear sentence or awkward explanation. If something reads wrong, is confusing, or a test looks unfair, please say so: [email protected].

The problems

Well-known interview problems keep the names people know them by, so you can find them. The statements, examples, tests and solutions here are written for this site. Company names mark the style of question reported for that company's interviews or assessments; algos.sh isn't affiliated with any of them.

Free, no ads

There are no ads and no third-party trackers; visits are counted with our own cookie-free counter. You can practise as a guest; your progress is saved with one cookie, and you can delete it at any time. The details are on the privacy page.