Python · C · C++
Write code. Get judged instantly.
Practice problems against real test cases, see exactly where a solution fails, and keep a record of every submission as you improve.
10 sper test case
Hiddentest cases
Isolatedsandbox per run
Instant verdicts
Accepted, Wrong Answer, Time Limit or Compile Error, with the details of every test case.
Real test cases
Each problem is checked against several hidden cases, so hard-coding the sample won't pass.
Safe by design
Every submission runs in its own throwaway container with no network and strict limits.
Track progress
See what you have solved, your acceptance rate and the full history of each attempt.