Pinterest Interview Questions

Pinterest Interview Questions

Practice 145 real Pinterest interview questions for 2026. Covers all top categories — Coding & Algorithms, Data Manipulation (SQL/Python), Analytics & Experimentation, Machine Learning, System Design — across Data Scientist, Software Engineer, Machine Learning Engineer, and Data Analyst roles. Real questions from actual interviews with detailed solutions. This collection leans hard on coding and algorithm problems for SWE candidates while giving equivalent weight to experiment design, SQL/Python analytics, and model evaluation for data roles, making it a focused resource for interview preparation for screens, virtual onsites, and take-home assignments. Expect interviews to evaluate algorithmic thinking, production design, experimental rigor, and clear data storytelling. For Data Scientists you’ll see carousel and billboard lift evaluation, weighted/random-sampling implementations, numpy/pandas and SQL analytics on category and video-time metrics, and survey-balance diagnostics. Software Engineers face prefix-matching, catalog update pipelines, sparse-matrix ops, grid/graph puzzles, and ads event reporting or blob storage design. Machine Learning Engineers get pin-search and recommender design, Naive Bayes/bagging implementation, hyperparameter generation, and sampling-by-score problems. Data Analysts encounter cohort and cancellation/rebooking metric questions. Prepare with timed coding drills, end-to-end A/B case studies, polished Python/SQL practice, and concise STAR stories for behavioral rounds.

145 Questions 1 Company08.07.2026
Showing 20 results
Role
Pinterest logo
Pinterest
Medium
Software Engineer Locked

Reconstruct route from unordered travel tickets

This question evaluates understanding of directed graph concepts and sequence reconstruction, assessing the ability to reason about ordered relationsh...

Coding & Algorithms
12
0
199 people solved
Jan 6, 2026
Pinterest logo
Pinterest
Easy
Machine Learning Engineer

Implement string-based rounding without floats

Coding You are not allowed to parse the input into a built-in floating type (to avoid overflow and precision issues). Work directly on strings. 1) Imp...

Coding & Algorithms
12
0
109 people solved
Dec 15, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

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(...

Coding & Algorithms
8
0
12 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Determine Pin Connections Through Common Boards

Scenario Pinterest boards contain many pins; need to infer relationships between pins. Question Given the membership lists of all boards, write a func...

Coding & Algorithms
19
0
58 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Design Algorithm to Minimize Payments in Expense-Sharing App

Scenario Expense-sharing app needs to settle debts among friends after a trip. Question Given a list of transactions (payer, payee, amount), design an...

Coding & Algorithms
28
0
96 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

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)...

Coding & Algorithms
4
0
53 people solved
Oct 13, 2025
Pinterest logo
Pinterest
Easy
Data Scientist

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...

Coding & Algorithms
11
0
87 people solved
Oct 13, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Compute CTR by format for new US users

You are given three tables. Write a single SQL query to compute click-through rate (CTR) by pin_format for NEW users in the US, where NEW users are th...

Data Manipulation (SQL/Python)
2
0
10 people solved
Oct 13, 2025
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Pinterest
Medium
Software Engineer

Implement a min-heap column allocator

You are given an integer k (number of columns) and an array posts of positive integers where posts[i] is the height of the i-th post. All columns star...

Coding & Algorithms
22
0
187 people solved
Sep 6, 2025
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Pinterest
Medium
Software Engineer

Cross-reference logs to flag spam numbers

You are given two data sets: ( 1) a call log containing phone numbers observed in calls and ( 2) a list of user reports where each entry is a phone nu...

Coding & Algorithms
7
0
130 people solved
Sep 6, 2025
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Pinterest
Medium
Software Engineer

Implement string-based big integer multiplication

Question Implement multiplyStrings(a, b) to multiply two non-negative integers given as decimal strings and return their product as a decimal string. ...

Coding & Algorithms
14
0
104 people solved
Sep 6, 2025
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Pinterest
Medium
Software Engineer

Design adjustable ID allocator

Question You manage a fixed global integer ID space [0, 999] (1000 IDs total) and a set of named buckets. Each bucket has a unique name and occupies a...

Coding & Algorithms
14
0
141 people solved
Sep 6, 2025
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Pinterest
Medium
Software Engineer

Decide target via subsequence plus/multiply expression

Question Given a sequence of positive 32-bit integers A and an integer target, determine whether there exists a subsequence of A (preserving order, us...

Coding & Algorithms
12
0
183 people solved
Sep 6, 2025
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Pinterest
Medium
Software Engineer

Round numeric string values

Question Given a numeric string, implement rounding to the nearest integer (e.g., '3.5' → '4', '100.01' → '100'). Follow-up: round to the last signifi...

Coding & Algorithms
14
0
32 people solved
Jul 29, 2025
Pinterest logo
Pinterest
Medium
Software Engineer

Find minimal time to serve customers

Find minimal time to serve customers You manage a bank with k tellers; teller i takes serviceTimes[i] minutes to serve one customer and works continuo...

Coding & Algorithms
5
0
89 people solved
Jul 28, 2025
Pinterest logo
Pinterest
Medium
Software Engineer

Find minimum shuttle transfers

Find minimum shuttle transfers You are given a collection of shuttle loops, each represented by a list of stop IDs that the loop visits in perpetuity....

Coding & Algorithms
9
0
93 people solved
Jul 26, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Design Efficient Multi-Level Access Control System

Scenario Multi-level access control lists (country → city) must be queried quickly. Question Design and implement a permission system where each geogr...

Coding & Algorithms
7
0
7 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Implement Data Structure for Top-K Elements in Streams

Scenario Analytics feature that must constantly report the K largest numbers seen so far. Question Implement a data structure that ingests a stream of...

Coding & Algorithms
27
0
79 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Data Scientist

Analyze Global Engagement and Impressions with SQL Queries

impressions +---------+---------+----------+----------------+ | user_id | country | category | impression_cnt | +---------+---------+----------+------...

Data Manipulation (SQL/Python)
45
0
6 people solved
Jul 12, 2025
Pinterest logo
Pinterest
Medium
Machine Learning Engineer Locked

Solve prefix, array, and string problems

This set of problems evaluates proficiency in string and array algorithm design—covering prefix search, subsequence matching, and maximal-area computa...

Coding & Algorithms
2
0
18 people solved
Apr 9, 2025

Frequently Asked Questions

How difficult are Pinterest interview questions for this 145-question set?
Pinterest interview difficulty varies by role and seniority. Across the 145 real questions in this set, expect medium-to-hard difficulty for software engineers with emphasis on clean algorithmic solutions and system tradeoffs, and moderate-to-hard for data scientists where product-focused experimentation, SQL, and causal reasoning are evaluated. Machine learning engineer rounds skew toward applied ML fundamentals and recommender/search design, while data analyst items are relatively straightforward metric calculations. Overall, interviews test both implementation fluency and product judgment — solving a problem correctly is necessary, but explaining assumptions, metrics, and tradeoffs is equally important.
What is the typical Pinterest interview process and where do these roles appear in the loop?
Pinterest interviews usually begin with a recruiter screen, followed by one or two technical screens tailored to the role, then a loop of 3–5 onsite or virtual interviews covering coding, system or ML design, and behavioral/manager rounds. Software engineer candidates see coding and system-design-focused rounds; data scientists face coding plus product-case and experimentation rounds; machine learning engineers combine coding with model design and recommender/search architecture; data analysts are asked metric and SQL problems. Expect the role to surface early in the loop during the technical screens so prepare role-specific artifacts and examples in advance.
How should I schedule preparation across the 145 real Pinterest interview questions — what timeline works best?
For 145 questions allocate a structured 6–8 week plan: weeks 1–2 reinforce fundamentals — arrays, strings, hashes, SQL joins/aggregates, and core ML statistics; weeks 3–5 work through the dataset: alternate role-specific blocks (coding for engineers, experiment and SQL cases for data scientists, model and recommender design for MLEs) and time-box solving full questions under interview conditions; final 1–2 weeks run timed mock interviews, system design walkthroughs, and behavioral STAR rehearsals. Review mistakes, write clean solutions, and practice explaining metrics and tradeoffs out loud before interviewing.
What are the key technical subtopics to prioritize from these Pinterest questions?
Prioritize the themes that appear repeatedly by role. For data scientists focus on experiment design and lift evaluation (carousel and billboard cases), weighted or random sampling implementations, SQL aggregation for top categories and engagement metrics, and handling survey biases. Software engineers should emphasize prefix/autocomplete patterns, pipeline and storage design, sparse-matrix algorithms, graph and grid search problems, and reliability for blob/event systems. Machine learning engineers need search/recommender architecture, model fundamentals (bagging, Naive Bayes), hyperparameter grid generation, and overfitting diagnostics. Data analyst items concentrate on retention and cancellation percent calculations.
What standout tips and common pitfalls should I watch for when prepping these Pinterest interview questions?
Lead with product context and metrics: state the business goal, choose evaluation metrics, and justify tradeoffs. Communicate assumptions, handle edge cases, and write tests or sample outputs for coding/SQL answers. For experiments, state randomization strategy, power implications, and bias controls. For ML, discuss features, regularization, and validation to avoid overfitting. Pitfalls include skipping requirement clarifications, ignoring NULLs or real data skew, overengineering a solution, and failing to link technical choices back to user or business impact. Practice concise storytelling for behavioral rounds and timed mock interviews for fluency.

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