You are given an array of integers. Your task is to return the k most frequent elements from the array.
If two or more elements share the same frequency, you may return them in any order.
If the number of unique elements is less than k, return all unique values.
Examples
Input: [1,1,1,2,2,3], k = 2
Output: [1,2]
Input: [1,1,1], k = 1
Output: [1]
Input: [1,2,3,2,3], k = 2
Output: [2,3]
Input: [1,2,3,4], k = 2
Output: [1,2]
This DoorDash VO interview question evaluates your ability to identify the k most frequent elements in an array.
The interviewer wants to see whether you can reason about:
- Counting frequencies efficiently
- Selecting the top k values without full sorting
- Using proper data structures such as HashMap, Min-Heap, or Bucket
- Articulating time and space complexity clearly
The expected solution must outperform O(n log n) sorting.
Most strong candidates propose an O(n log k) heap-based approach or an O(n) bucket-based solution.
This question is common in VO interviews because it tests clarity of thought, data-structure fluency, and coding execution under time pressure.
The VOprep team has long accompanied candidates through various major company OAs and VOs, including Doordash, Google, Amazon, Citadel, SIG, providing real-time voice assistance, remote practice, and interview pacing reminders to help you stay smooth during critical moments. If you are preparing for Tiktok or similar engineering-focused companies, you can check out our customized support plans—from coding interviews to system design, we offer full guidance to help you succeed.
