Code RoomSMOTE before split contaminates test
HardPrep Room Coding #4226

SMOTE before split contaminates test

Vibe & agenticAlgorithms & data structuresSenior–Staff~19 min

An AI addressed class imbalance with SMOTE before the split. Validation recall jumps to 0.95 but real-world recall is mediocre. Identify the two-part mistake.

Implement
resampled_split_counts(labels: list[int], in_test: list[bool]) → list[int]
Examples
in[[0,0,0,0,1,0,0,1],[false,false,false,false,false,true,true,true]]out[4,4,2,1]
in[[1,0],[true,true]]out[0,0,1,1]
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 19 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.