Find Top K Frequent Elements in an Array (Hash Map + Bucket Sort)

Problem Statement

Given an integer array `nums` and an integer `k`, return the `k` most frequent elements in O(N) time complexity. You may return the answer in any order.

Target Complexity

Time:

O(N) with Bucket Sort (or O(N log K) with Min-Heap)

Space:

O(N) for frequency map and buckets

Interview Talking Points:

• Explain why sorting the map entries takes O(N log N), while Bucket Sort achieves optimal O(N) linear time.
• Explain the Min-Heap approach for streaming data where total size N is unknown in advance.

Solution Editor (JavaScript)

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Test Results

Returns top 2 frequent elements from array

Test #1

Handles single element array

Test #2

Handles negative numbers and distinct frequencies

Test #3