Coding problems

33 Python problems (NumPy, Python, or PyTorch in the language dropdown) and 27 SQL warehouse problems. Filter by role — every role’s questions live on this list. Easy problems are free; medium and hard need Pro.

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SearchLanguageStatusDifficultyTopicRoleTrackCompany

Problem	Language	Difficulty	Track
1. Mean ~5 min · Google, Meta	Python	easy	Python Foundations
2. Mean squared error ~8 min · Google, OpenAIPro	Python	medium	ML metrics
3. Mean absolute error ~6 min · Amazon, GooglePro	Python	medium	ML metrics
4. ReLU ~5 min · Google, Meta	Python	easy	Python Foundations
5. Dot product ~6 min · Google, NVIDIAPro	Python	medium	Python Foundations
6. Argmax ~5 min · Meta, ApplePro	Python	medium	—
7. Clip ~6 min · Stripe, GooglePro	Python	medium	Python Foundations
8. Flatten ~5 min · Amazon, NetflixPro	Python	medium	Python Foundations
9. Min-max normalize ~10 min · Google, DatabricksPro	Python	hard	—
10. Softmax ~12 min · OpenAI, GooglePro	Python	hard	Tensors & ranking
11. Mean ignoring NaN ~8 min · Tesla, GooglePro	Python	medium	Stats the analyst pad asks
12. Population variance ~8 min · Meta, Two SigmaPro	Python	medium	Stats the analyst pad asks
13. Population standard deviation ~8 min · Jane Street, GooglePro	Python	medium	Stats the analyst pad asks
14. Median ~8 min · Amazon, BloombergPro	Python	medium	Stats the analyst pad asks
15. Cumulative sum ~6 min · Stripe, UberPro	Python	medium	—
16. Cosine similarity ~12 min · OpenAI, GooglePro	Python	hard	Tensors & ranking
17. Moving average ~10 min · Bloomberg, QuantCoPro	Python	hard	Stats the analyst pad asks
18. Unique sorted ~6 min · Apple, AmazonPro	Python	medium	—
19. Count a value ~5 min · Meta, NetflixPro	Python	medium	Python Foundations
20. Weighted mean ~8 min · Airbnb, GooglePro	Python	medium	Stats the analyst pad asks
21. R-squared ~12 min · Databricks, GooglePro	Python	hard	ML metrics
22. Manhattan distance ~6 min · Uber, LyftPro	Python	medium	—
23. Log-softmax ~12 min · OpenAI, AnthropicPro	Python	hard	Tensors & ranking
24. Pearson correlation ~14 min · Two Sigma, CitadelPro	Python	hard	Tensors & ranking
25. Binary cross-entropy ~14 min · OpenAI, AnthropicPro	Python	hard	ML metrics
26. Precision ~12 min · Meta, GooglePro	Python	hard	ML metrics
27. Top-k indices ~12 min · Google, NVIDIAPro	Python	hard	Tensors & ranking
28. Z-score ~12 min · Jane Street, CitadelPro	Python	hard	Stats the analyst pad asks
29. Shannon entropy ~12 min · DeepMind, GooglePro	Python	hard	Tensors & ranking
30. Recall ~12 min · Meta, GooglePro	Python	hard	ML metrics
31. F1 score ~14 min · OpenAI, AnthropicPro	Python	hard	ML metrics
32. KL divergence ~14 min · DeepMind, Two SigmaPro	Python	hard	Tensors & ranking
33. Huber loss ~14 min · NVIDIA, Jane StreetPro	Python	hard	Tensors & ranking
34. Completed revenue by country ~10 min · Stripe, Shopify, SquarePro	SQL	medium	SQL Foundations
35. Top products by units sold ~10 min · Amazon, Walmart, InstacartPro	SQL	medium	SQL Foundations
36. Who reports to Ben ~6 min · Google, Meta, MicrosoftPro	SQL	medium	SQL Foundations
37. Orders with more than one line ~8 min · Instacart, DoorDash, Shopify	SQL	easy	SQL Foundations
38. Event funnel by stage ~10 min · Meta, Snap, PinterestPro	SQL	medium	SQL Foundations
39. Orders with no payment ~10 min · PayPal, Capital One, StripePro	SQL	medium	Warehouse SQL Core
40. Cancel rate by country ~12 min · Uber, DoorDash, LyftPro	SQL	medium	Warehouse SQL Core
41. Daily completed revenue ~10 min · Meta, Netflix, SpotifyPro	SQL	medium	Warehouse SQL Core
42. Customer lifetime summary ~15 min · Airbnb, Booking, ExpediaPro	SQL	medium	Warehouse SQL Core
43. Running total of daily revenue ~12 min · Stripe, Airbnb, BookingPro	SQL	medium	Windows & Time Series
44. Seven-day moving average ~14 min · Netflix, Spotify, UberPro	SQL	hard	Windows & Time Series
45. Day-over-day revenue growth ~14 min · Meta, Uber, LyftPro	SQL	hard	Windows & Time Series
46. Revenue share by country ~12 min · Amazon, Shopify, MetaPro	SQL	medium	Windows & Time Series
47. Latest order per customer ~12 min · Shopify, Square, InstacartPro	SQL	medium	Ranking & Dedup
48. Top two products per category ~14 min · Amazon, Walmart, TargetPro	SQL	hard	Ranking & Dedup
49. Salaries above the department average ~14 min · Google, Microsoft, BloombergPro	SQL	hard	Ranking & Dedup
50. Reconcile orders against payments ~14 min · Stripe, Capital One, WisePro	SQL	hard	Data Quality & Hard SQL
51. Traffic source from JSON payload ~12 min · Snowflake, Databricks, AirbnbPro	SQL	medium	Data Quality & Hard SQL
52. Payment method mix by day ~12 min · Stripe, PayPal, AdyenPro	SQL	medium	Data Quality & Hard SQL
53. Median completed order amount ~18 min · Capital One, JPMorgan, RobinhoodPro	SQL	hard	Data Quality & Hard SQL
54. Sessionize events (30-minute gap) ~20 min · Netflix, Spotify, AirbnbPro	SQL	hard	Data Quality & Hard SQL
55. Customers who cancelled and completed ~16 min · Stripe, Adyen, Checkout.comPro	SQL	hard	Data Quality & Hard SQL
56. Customers who bought every category ~18 min · Amazon, Instacart, WalmartPro	SQL	hard	Data Quality & Hard SQL
57. Second order within seven days ~18 min · Shopify, DoorDash, UberPro	SQL	hard	Data Quality & Hard SQL
58. Hours from order to settlement ~18 min · Stripe, Adyen, PayPalPro	SQL	hard	Data Quality & Hard SQL
59. First-touch traffic source ~18 min · Airbnb, Shopify, MetaPro	SQL	hard	Data Quality & Hard SQL
60. Customers above average order volume ~16 min · Amazon, DoorDash, UberPro	SQL	hard	Data Quality & Hard SQL

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