Repair division by zero
Difficulty: Easy
Repair the buggy starter to meet this contract: Return a/b for finite numbers, or null/None when b is zero.
Test-design prompt
Add 0/0 and explain why checking the numerator does not prevent failure.
Before editing, identify a minimal failing input and predict the result. After repairing, rerun the regression cases and explain why the old implementation failed.
Examples
1, 0None0, 20.06, -2-3.0Constraints
Inputs are JSON-compatible. Unless a tighter bound is stated, lists have at most 200 elements, strings at most 1000 characters, and integers are within -1000000..1000000. Do not mutate inputs. Use only the browser runner; no file or network access. Preserve the required function signature.
Review lesson: Read errors before changing codeA little nudge
Reveal one hint at a time. Give yourself a moment to try it.
Worked solution
Try your own approach first, then compare the reasoning.
Complexity
Ready when you are
Write your solution, then run it against the practice tests.
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