Data Engineer Coding & Algorithms Interview Questions
Practice 49 real Coding & Algorithms interview questions for Data Engineer roles. From companies including Meta, Interactive, Amazon, Apple, Bytedance.
"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"
"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"
"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."
"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."
"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."
"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."
"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."
"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."
"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."
"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."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Implement Portfolio Trading Optimizer
You are given an array prices, where prices[i] is the price of one stock on day i. You may perform multiple buy/sell transactions over the period, but...
Write SQL Data Transformation Queries
Use SQL to solve the following data transformation tasks. Assume standard SQL features are available, including window functions and recursive common ...
Implement Election Report and Banking Pipeline
You are given two independent data engineering coding tasks. Task 1: SQL Election Exit Poll by State Report An election analytics team needs a report ...
Compute User Login Streaks
Given a table user_login_log with the following columns: - user_id: the user identifier - login_date: the calendar date of a login event A user may ha...
Write SQL using joins and window functions
SQL Coding: Rank within Groups with Joins You are given two tables: accounts - account_id (string) - customer_id (string) - segment (string) — e.g., "...
Write SQL for first share and closest collaborator
You are given event data about users viewing design files. Assume the following tables: - files(file_id, creator_id) - creator_id is a VARCHAR user ...
Write SQL revenue and anomaly queries
You are given two tables. Table: transactions | Column | Type | Description | |---|---|---| | transaction_id | int | Unique identifier for each transa...
Implement Game Metadata Lookups
You are given a list of game metadata records. Build an in-memory representation that can store each game's name, release date, platforms, genre, publ...
Build a Least-Recently-Used Store
Implement an in-memory key-value store with least-recently-used eviction. The store is initialized with a positive integer capacity and supports two o...
Encode and Rebuild a Binary Tree
Design two functions for a binary tree: - encode(root) -> string - decode(data) -> root Each tree node contains an integer value and has up to two chi...
Write SQL for app metrics
You are given a simplified schema for a photo-sharing app: - users(user_id, user_name, joined_at) - photos(photo_id, user_id, created_at) - follows(fo...
Compute Minimum Days with Cooling Period
You are given an ordered list of products to manufacture and a non-negative integer space representing the cooling period. Each day, you may either: -...
Implement two string utility functions
Implement the following Python functions: 1. number_of_character(string, char) - Return the number of times character char appears in string. - ...
Validate an IPv4 address string
Given a string s, determine whether it is a valid IPv4 address. A valid IPv4 address: - Has exactly 4 parts separated by dots (.): x1.x2.x3.x4 - Each ...
Find Top Creators and Login Streaks
Solve the following two interview-style tasks. Task 1: Top creators by likes You are given a list of like events for a business-facing creator platfor...
Write queries for follows and bookings
You are given tables/logs from a consumer app. Solve the following independent tasks. Part A — Active following as of a date (SQL) You have a follow e...
Compute transaction fees from a CSV string
You are given a CSV string representing a list of payment transactions. Write a function that parses the CSV and returns a CSV string with the total p...
Write SQL for basic user metrics
You are given a simplified schema for a fictional social app called Nextagram: - users(user_id PK, username, created_at TIMESTAMP) - follows(follower_...
Solve two string problems
You are asked to solve the following two coding problems. 1. Count unique Morse code translations You are given an array of lowercase English w...
Aggregate user logs into 30-minute sessions
You are given a CSV file with columns: user_id | log_datetime | topic Example input rows (already in time order for the same user): - 001 | 2025-03-01...