Explain the time complexity of building a Heap.

Updated Apr 28, 2026

Short answer

O(N) when using the bottom-up approach, not O(N log N).

Deep explanation

Intermediate concepts focus on problem-solving patterns. O(N) when using the bottom-up approach, not O(N log N).

Real-world example

Real-time leaderboards in gaming.

Common mistakes

  • Using a Max-Heap to find the K-th largest (which is less efficient than a K-sized Min-Heap).

Follow-up questions

  • Time complexity of nlargest?

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