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Code RoomInteger overflow and division truncation
HardPrep Room Coding #4613

Integer overflow and division truncation

Vibe & agenticAlgorithms & data structuresSenior–Staff~18 min

You asked an AI assistant for a Rust function computing the average of a slice of `u32` readings (sensor values). It produced:

It passes `average(&[10, 20, 30])`. What are the two distinct failure modes, and what triggers each?

Implement
average_reading(readings: list[int]) → int
Examples
in[[10,20,30]]out20
in[[]]out-1
in[[4294967295,4294967295,4294967295,4294967295]]out4294967295
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.

0:00 of about 18 min

Vibe & agentic: describe the solution in plain language (or narrate it) and the coach grades your approach.

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.