Implement k-means from scratch
Last updated: May 4, 2026
Quick Overview
Write a clean implementation of logistic regression without using ML libraries.
Waymo
May 4, 202644
6
4,359 solved
Write a clean implementation of logistic regression without using ML libraries.
Waymo asks this during the Phone Screen 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
- Explain the mathematical foundations with clarity
- Discuss practical implementation considerations and hyperparameter tuning
- Analyze the technique's strengths and weaknesses for different data types
- Demonstrate understanding of evaluation methodology and metrics
- Connect theory to real-world applications with concrete examples
Key Topics to Cover
How to Approach This
- Understand the bias-variance trade-off. High training accuracy but low test accuracy signals overfitting.
- Choose evaluation metrics carefully based on the problem. Accuracy alone is often insufficient.
- Feature engineering is often more impactful than model selection.
- Know when to use tree-based models (tabular data) vs neural networks (unstructured data).
- Handle class imbalance with SMOTE, class weights, or appropriate loss functions.
Possible Follow-up Questions
- When would you prefer a simpler model over a complex one?
- What are the computational costs of this approach at scale?
- How would you ensure reproducibility in your ML pipeline?
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Explore ML Interview PrepSample Answer
Core Concept Explanation
Start with a clear, intuitive explanation of the concept. Use analogies when helpful. Then go deeper into the mathematical foundations: **Key Intuiti...
Practical Application
**When to use**: Describe the scenarios where this technique is most effective. What data characteristics favor it? **When NOT to use**: Common pitfa...
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