Coding & Algorithms Interview Questions
Practice 3,469 real coding and algorithms interview questions reported from interviews at Meta, Amazon, Google, Uber and Microsoft. The mix follows what these loops actually ask: arrays and strings, hash maps, two pointers and sliding windows, binary search, linked lists, trees and graphs, BFS and DFS, recursion and backtracking, dynamic programming, heaps and priority queues, and the occasional design-a-data-structure round. Roughly four in five are rated medium, which is where most technical screens sit; 477 are hard and cluster in onsite loops. 3,033 of them open in a console where you can run your solution against the test cases in Python, Java, C++ or JavaScript. 2,712 come from Software Engineer interviews, with the rest from Machine Learning Engineer, Data Scientist and Data Engineer loops, and 404 were set as take-home projects rather than live sessions.
"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."
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"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."
Build a Quadtree and Analyze a Graph
Solve the following two coding problems. 1. Build a quadtree from an image You are given an N x N matrix of integers representing an image, where N is...
Optimize Trapping Rain Water
Question LeetCode 42. Trapping Rain Water – implement a brute-force solution, analyze its complexity, then optimize to an O(n) solution with O(n) spac...
Construct tree from inorder & postorder
Question LeetCode 106. Construct Binary Tree from Inorder and Postorder Traversal – Given the inorder and postorder traversal arrays of a binary tree,...
Solve bank, password, expression algorithm tasks
Solve bank, password, expression algorithm tasks Implement a banking system that supports four specified operations within 90 minutes. Implement a pas...
Solve tree, graph, sliding-window problems
Question LeetCode 103. Binary Tree Zigzag Level Order Traversal – given a binary tree root, return its zigzag level-order traversal. LeetCode 207. Cou...
Solve linked-list and top-K algorithm tasks
Question Given a singly linked list, return the k-th node counted from the end. Given an integer array, return the top k most frequent numbers. Given ...
Solve Logic Puzzles: Algorithms and Proofs Required
Solve Logic Puzzles: Algorithms and Proofs Required Scenario On-site logic/algorithm quiz with hiring manager and VP Question Solve six AMC-8–level ma...
Optimize Travel Costs and Generate Rotational Symmetric Numbers
Scenario You are building a travel-search engine that must 1) show customers the cheapest round-trip they can book if departure and return prices vary...
Count Word Frequency and Print Top Three Words
Scenario First-round Python coding screening Question Using only basic Python, write a function that receives a list of strings and returns a dictiona...
Connect-N on an Infinite Board with Gravity
You are asked to implement a variant of the classic Connect Four game, played on an unbounded board. Game Rules - The board consists of vertical colum...
Implement a key-value CRUD store
Implement an in-memory key–value store that supports create, read, update, and delete operations. Expose APIs such as put(key, value), get(key), updat...
Validate course catalog dependencies
Design a function to validate an e-learning course catalog. You are given: ( 1) a set of course IDs, and ( 2) a list of prerequisite pairs (u, v) mean...
Design document editor with undo/redo and batching
Design a document-editing layer that supports applying edits and undo. Implement an API with apply(Operation op), undo(), and getText(). Then add tran...
Solve rotating-lock BFS with blockers
You are given a 4-digit lock starting at "0000". In one move, you may pick a single position and rotate it +1 or −1 with wrap-around (0→9 on −1, 9→0 o...
Describe Java 8 features
Describe Java 8 features What are the key new features introduced in Java 8? Explain when and how you would use lambda expressions, the Stream API, Op...
Design duplicate-file detection using size
You are given a large POSIX-like filesystem containing millions of files across nested directories. Design an algorithm to find groups of duplicate fi...
Design an Animal Chess OOP simulation
Design and implement a simplified Animal Chess (Dou Shou Qi) game using object-oriented principles. Include: 1) Piece classes Elephant, Lion, Tiger, L...
Solve transaction aggregation and search tasks
Solve transaction aggregation and search tasks Complete the following coding tasks: (a) Given a list of transactions, each with userId and amount (cre...
Analyze time and space complexity
Analyze time and space complexity For any algorithm you implement, analyze its time and space complexity using Big-O notation. Derive and justify the ...
Implement sliding-window moving average
Design a class MovingAverage that supports a constructor MovingAverage(k) and a method next(val) returning the average of the last k values from a dat...