Repair an empty-input crash
Difficulty: Easy
Repair the buggy starter to meet this contract: Return the first integer in values, or null/None if empty.
Test-design prompt
Add a case where the first value is zero and explain why a truthiness fallback fails.
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
[]null[0, 2]0[-1]-1Constraints
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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