Python interview question: top k frequent elements

MediumHash maps

For the app’s “Frequently ordered” block, return the k most frequent ids in product_ids (one id per order line), most frequent first. On a tie, the smaller id comes first. If there are fewer than k distinct products, return them all.

def top_k_products(product_ids: list[int], k: int) -> list[int]:

Example

• product_ids = [101, 205, 101, 333, 205, 101, 412], k = 2 → [101, 205]
• product_ids = [8, 3, 8, 3, 5], k = 1 → [3]8 and 3 both occur twice; the smaller id wins

Skills it tests

• Frequency counts
• Tie breaking

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