An online compiler built for DSA practice
Write, run and check interview solutions without installing anything. The editor runs code in 9 languages, grades it in 4. Python and JavaScript run inside your browser, so there is no queue and your code stays on your machine. The other languages run on free public code runners.
Run, then Submit
Run executes your code on the sample cases you can see, or on your own input. Submit grades it against the full hidden test set, the way an online judge does. Graded Submit works in Python, JavaScript, C++ and Java on 356 of the curated problems, and every graded attempt is kept with its code, so you can see what changed between a wrong answer and an accepted one.
Watch your code run
Stuck on why a loop gives the wrong answer? Python and JavaScript code can be traced one line at a time. You see each variable change as the line executes, instead of guessing from print statements.
Open a problem straight into the editor
Every problem on DSA Tracker opens here with its statement, a starter template and its tests. Your code is saved per problem in this browser, so you can close the tab and pick up where you stopped.
Questions
- Is the compiler free?
- Yes. Running and tracing code is free, and there is nothing to install.
- Which languages can I submit in?
- Python, JavaScript, C++ and Java. C, Go, Rust, Kotlin and TypeScript can Run but not Submit.
- Where does my code run?
- Python and JavaScript run in your browser. C++, Java and the other languages are sent to free public code runners, and the output comes back to the page.
- Can I use it for problems that are not on DSA Tracker?
- Yes. Open the editor without a problem and it is a plain scratchpad: paste any code, add your own input and press Run.