Implement k-means from scratch

Last updated: January 25, 2026

Quick Overview

Write a clean implementation of k-means without using ML libraries.

Supabase
Machine Learning
Machine Learning Engineer
Supabase
January 25, 2026
Machine Learning Engineer
Onsite
Machine Learning
Hard

17

6

2,882 solved


Write a clean implementation of k-means without using ML libraries.

Supabase asks this during the Onsite to assess your depth in ML. They expect you to discuss the mathematical foundations, practical considerations, and common pitfalls when applying these techniques in production.

What the Interviewer Expects
  • Derive key equations and explain the optimization process in depth
  • Discuss state-of-the-art variations and recent research developments
  • Analyze computational complexity and scalability
  • Implement core components from scratch with clean code
  • Discuss production deployment challenges and solutions
  • Compare with cutting-edge alternatives and justify your recommendation
Key Topics to Cover
Supervised vs unsupervised learning
Feature importance and selection
Model interpretability and explainability
Cross-validation and model evaluation
How to Approach This
  1. Understand the bias-variance trade-off. High training accuracy but low test accuracy signals overfitting.
  2. Choose evaluation metrics carefully based on the problem. Accuracy alone is often insufficient.
  3. Feature engineering is often more impactful than model selection.
  4. Know when to use tree-based models (tabular data) vs neural networks (unstructured data).
  5. Handle class imbalance with SMOTE, class weights, or appropriate loss functions.
Possible Follow-up Questions
  • What are the computational costs of this approach at scale?
  • When would you prefer a simpler model over a complex one?
  • How would you ensure reproducibility in your ML pipeline?
  • What regularization technique would you use and why?
Sharpen Your Skills on Codemia

Practice similar problems with our interactive workspace, get AI feedback, and track your progress.

Explore ML Interview Prep
Sample Answer
Core Concept: K-Means Clustering

K-Means is an unsupervised learning algorithm used for clustering data points into K distinct groups based on feature similarities. The core idea is to minimize the intra-cluster variance, which is th...

How It Works: Algorithmic Mechanism

K-Means operates in two main steps: assignment and update. In the assignment step, each point is assigned to the nearest centroid:

  • For each data point xjx_j, assign it to cluster CiC_i wher...

Submit Your Answer
Markdown supported

Related Questions