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Vibe codingHardvc-g035
Subject Ai code reviewLevel Senior~18 minCommon in Networking & APIs interviewsIndustries Software development

Question

An AI assistant wrote this Python to extract all dollar amounts from log lines and sum them, using a precompiled regex for speed:

python
import re AMOUNT = re.compile(r"\$(\d+(\.\d{2})?)") def sum_amounts(lines):    total = 0.0    for line in lines:        for m in AMOUNT.finditer(line):            total += float(m.group())    return total

On your three sample lines it returns the right total. What's the contract bug, and what input proves it?

What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts
Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.