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Top 50 Data Scientist Interview Questions

The 50 most important questions to prepare for Data Scientist interviews. Questions from real interview reports rank first. Updated weekly.

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~17htotal time
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1
SQL & Data ManipulationStart here. 45 questions · ~923 min
7-Day Rolling Active UsersMedium
Practice
Recently asked

Compute daily active users and a 7-day rolling average using a CTE, distinct counts, and window functions.

Window FunctionsDate FunctionsRunning TotalsMetaAcumenCorning
Analyze Customer Purchase Trends with Window FunctionsMedium
Practice
Recently asked

Calculate the monthly spending trends for customers using window functions and joins.

The Home DepotHewlett Packard EnterpriseConvoy
Calculate Monthly Sales Growth by Product CategoryMedium
Practice
Recently asked

Calculate month-over-month sales growth for each product category using JOINs and window functions.

JoinsAggregationsWayfairFanaticsREVOLVE
Compare Weekly User Activity TrendsMedium
Practice
Recently asked

Aggregate user activity by week, then use LAG to compare sessions and watch time versus the prior active week.

Window FunctionsLag/LeadDate FunctionsPublishers Clearing HouseNBCUniversalInteractive Process Technology
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2
Coding5 questions · ~103 min
Check Whether Two Strings Are AnagramsEasy
Practice
Recently asked

Use a hash map of character counts to determine whether two strings are anagrams in linear time.

Hash TablesStringsSortingAmazonMeta ITWalmart
Normalize and Count Word FrequenciesEasy
Practice
Recently asked

Count normalized word frequencies in a string using clean helper functions and a hash table.

abstractionTestingFrameworksCapital One
Merge Sorted Customer ID ArraysEasy
Practice
Recently asked

Merge two sorted arrays using two pointers and remove duplicates in one pass.

deduplicationArraysSortingCapital One
Shortest Professional Connection PathMedium
Practice

Use BFS on an undirected graph to return the shortest connection path between two people.

shortest pathbfsGraphsMercor
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