Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the type errors pattern
Totals that concatenate, sorts that put 10 before 9, comparisons that refuse to run.
What went wrong: the dict's keys are the text "1" and "2". Looking up the number 1 is a different key, so it is not found.
The fix: return sum(counts[str(i)] for i in ids)
Remember: in JSON, object keys are always text. In Python, 1 and "1" are different keys.
The pattern behind it: type errors.
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<iframe src="https://trybughunt.com/embed/76553949-5d34-4e95-9958-e5ebe625a5c3" title="Debugging challenge: Lookup says KeyError: 1, but 1 is right there" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/76553949-5d34-4e95-9958-e5ebe625a5c3">TryBugHunt</a></p>