Challenges
How does it work?
- Pick a challenge by category, language, or difficulty (kyu).
- Write your solution in the code editor.
- Submit to check if your code passes the test suite.
- Rank up from 8 kyu (beginner) toward 1 dan (master).
Sharpen your skills. Rank up from 8 kyu to 1 dan.
4 kyu
Python
Race Condition Detective
This banking transfer function has a race condition. Identify it, explain why it's dangerous, and write a test that c...
Bug Hunting
60 XP
7 kyu
Python
Spot the Boundary Bug
This function calculates shipping cost based on weight. It has 3 boundary value bugs. Find them by writing failing te...
Bug Hunting
20 XP