The Runtime Theory
mediumLeetCode#frequency-map#heap#bucket-sort

Top K Frequent Elements

Return the k values with the highest frequency; define a deterministic tie policy for your implementation.

The Runtime Theory Team25 min read
Solve it

Solving happens on the judge — come back and mark it done

Sample cases

innums=[1,1,1,2,2,3], k=2

out[1,2]

innums=[1], k=1

out[1]

innums=[4,4,5,5,6], k=2

out[4,5]

Return the k values with the highest frequency; define a deterministic tie policy for your implementation.

A good solution should

  • State the invariant or decision rule that makes the approach correct.
  • Explain the time and space complexity in terms of the input sizes and required output.
  • Handle empty, minimal, duplicate, and boundary-shaped inputs covered by the contract.

Reasoning prompt

Compare a size-k heap with bucket grouping. State time and space costs and test ties at the cutoff.

Use the linked judge for the canonical problem. The examples above are compact TRT checks; write additional cases before submitting, especially for the boundary that tends to break your chosen invariant.

More practice in this topic

One dispatch a week

The trace behind each problem, the tradeoff that explains it, and one technical dispatch per week — no noise.

One technical dispatch per week. No noise.

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