Pinterest Data Scientist Interview Questions
Preparing for Pinterest Data Scientist interview questions demands focused interview preparation across coding, product thinking, and experimentation. Pinterest’s DS loop typically blends practical SQL and Python problem-solving with statistical reasoning and product-metric case work, so expect questions that test your ability to extract and manipulate data, design and evaluate experiments, and translate analyses into product recommendations. ([interviewquery.com](https://www.interviewquery.com/interview-guides/Pinterest-Data-Scientist?utm_source=openai)) The process usually starts with a recruiter screen, moves to a technical phone or take-home assessment, and—if advanced—an onsite loop of domain, coding/SQL, statistics, and behavioral interviews; intern/new‑grad tracks sometimes use CodeSignal for initial screening. To prepare, rehearse live SQL and Python problems, review experiment design and key metrics, and craft concise project stories that show impact and tradeoffs. Practicing timed coding on collaborative pads and walking interviewers through your reasoning will be especially valuable. ([pinterestcareers.com](https://www.pinterestcareers.com/interviewing/?utm_source=openai)
"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"
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"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."
"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
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Design rigorous A/B test and causal analysis
Experiment Design and Causal Inference: Multi-part Problem Context: You are designing a high-traffic web A/B test on a binary conversion metric. Answe...
Recover causal effect without a control group
Post-hoc Causal Estimation After a Failed A/B Rollout Context An intern accidentally shipped a feature to 100% of eligible users for 5 consecutive day...
Implement scalable prime generator
Write a function first_n_primes(n) that returns the first n prime numbers in ascending order. Constraints: - 1 ≤ n ≤ 100,000. - Aim for O(n log log n)...
Investigate Homepage Experiment Without Control Group: Methods and Metrics
Homepage Experiment Without a Control Group A social-media homepage team is analyzing a personalized feed. An intern accidentally launched a treatment...
Explain your ML project end-to-end
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Estimate Highway Billboard Impressions Using Traffic Data
Estimating Highway Billboard Reach and Impressions An out-of-home advertising team wants to estimate reach and impressions for a single highway billbo...
Implement weighted random choice
Implement a simplified version of np.random.choice without calling the built-in function. You are given an array items of length n and an optional pro...
Determine Appropriate Statistical Test for Comparing Means
Statistical Test for Comparing Mean Active Minutes You have two weeks of experiment data for a new algorithm. The primary metric is user active minute...
Assess Cultural Fit and Self-Reflection in Hiring Process
Behavioral Interview: Cultural Fit and Self-Reflection In a Pinterest Data Scientist onsite loop, hiring-manager and cross-functional panels may use p...
Implement np.random.choice
Implement a function similar to numpy.random.choice. Function signature choice(a, size=None, replace=True, p=None) -> samples Requirements - a can be:...
Transform nested dicts with pandas apply/lambda
Given a pandas DataFrame df with columns: user_id (int), ts (datetime64[ns]), events (list of dicts), attrs (dict). Example rows (conceptual): user_id...
Compute average unique pins per user
Task: Average Unique Pins Per User You are given a mapping from user IDs to their lists of pin IDs. Implement a function that computes the mean number...
Implement Jackknife and Random Choice
Write Python code for two implementation tasks without using np.random.choice directly: 1. Jackknife-style resampling. Given a one-dimensional collect...
Find available reservation time slots
Problem You are building an API to show which time slots are available for booking at a restaurant. You are given: - The restaurant’s opening hours (p...
Implement DelayQueue with Idempotent Task Execution
Scenario Message broker offers DelayQueue where tasks execute at future timestamps, ensuring idempotency on duplicate IDs. Question Implement a delay ...
Design Data Structure for Sparse Matrices Operations
Scenario Analytics engine stores extremely sparse numeric matrices. Question Design a data structure to store two sparse matrices and implement print(...
Optimize Hyper-parameter Search to Prevent Combinatorial Explosion
Enumerating Grid Search and Avoiding Hyperparameter Explosion You are building a hyperparameter optimization service that must enumerate every grid-se...
Write SQL to compute max-overlap lists
Invented schema and sample data below. Assume 'today' is 2025-09-01 and 'last 7 days' means 2025-08-26 through 2025-09-01 inclusive. Only consider lis...
Aggregate video time and unique pins in Python
Part A (category by average time for videos): You receive a list of pin engagement rows and a category map. pins = [ {"pin_id": 10, "category_id": 1,...
Verify Machine-Learning Fundamentals for E-commerce Recommendation Platform
Verify Machine-Learning Fundamentals for E-commerce Recommendation Platform Rapid ML Fundamentals Check — Recommender Systems Context You are intervie...