Is the number a grade? Is it arbitrary?
Unexpected that you have a "style50" but no "check50" on that submission.
Most problems have two scores, a
check50 score based on correctness (uses a list of test cases), and a
style50 score based on style (for C, read the C style guide, for Python it's the PEP-8)
You can click the "check50" or "style50" for a more detailed report.
The total score is made from 75% correctness and 25% style, you need 70% for a problem to pass. (A few problems are 100% correctness instead)