Coding & Algorithms Interview Questions
Practice 3,013 real Coding & Algorithms interview questions for 2026. Coding & Algorithms interview questions for top tech firms like Meta, Amazon, Google, Uber, and TikTok — real questions from actual interviews with detailed solutions — to power your interview preparation. This collection is sharply focused on algorithmic patterns (arrays, strings, sliding windows, trees/graphs, dynamic programming, greedy, two-pointers, and hashing), clean, review-ready code, and the explanation skills that distinguish hires. In 2026 expect familiar medium-to-hard problems plus newer twists: AI-enabled or multi-file coding rounds at some companies, more emphasis on explainability and edge-case reasoning, and occasional real-world performance constraints (streaming, concurrency, memory limits). Interviewers evaluate problem framing, algorithm choice, complexity trade-offs, test-case thinking, and communication under time pressure. Best prep mixes pattern-based practice, timed mock interviews, code-review style polishing, and rehearsed explanations of complexity and tradeoffs. Focus your last-mile prep on writing correct, readable code quickly and on explaining why your solution is robust and efficient for production scenarios.

"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."
Find Top Errors in Time Window
Implement a function that analyzes request-response logs stored as JSON records. Each record contains a timestamp, a response status, and optionally a...
Design Sliding-Window Average Tracker
Design a class that tracks records in a sliding time window. Implement the following API: - init(time_window): initialize the object with a window siz...
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 ...
Calculate charge with a single price override
You are billing a customer based on usage intervals and a single temporary price override. Definitions - A usage record is an interval [start, end) wh...
Implement retrieval and evaluation for a simple RAG
Task You are given a small “toy RAG” notebook setup with helper utilities. You have a corpus of text passages stored in a pandas DataFrame docs_df wit...
Implement lossless dictionary encoding and decoding
Dictionary encoding is a lossless compression technique for a list of tokens. You are given an input string consisting of words separated by commas, e...

Update a Neuron Grid
You are given an m x n integer matrix neurons. - A cell is a firing neuron if its value is 0. - A cell is a non-firing neuron if its value is greater ...
Solve sliding window, heap, DP, in-place tasks
You are given several LeetCode-style coding tasks. Implement each with the stated time/space goals and handle edge cases. 1) Sliding Window: longest s...
Check Meeting Attendance With Breaks
You are given a list of appointment intervals for a single day and a mandatory break time between any two consecutive appointments. Each interval is r...
Implement a Snapshot Set Iterator
Design and implement a mutable SnapshotSet data structure. The set stores unique keys and supports normal set operations, plus snapshot iterators. Imp...
Implement Article Vote Tracking
We are building an in-memory vote management service for an online news platform. Users can upvote or downvote published articles, and we want to trac...
Find minimal rate k and subset sum
Question LeetCode 875. Koko Eating Bananas — Given vault sizes [3, 6, 7, 11] and time h = 8 hours, find the minimum integer rate k (vault units per ho...
Compute Turnstile Crossing Times
You are given n people waiting to use a single-door turnstile. Each person has: - time[i]: the time when person i arrives at the turnstile. - directio...
Find Each Cell's Nearest Source
Given an m x n grid containing 1 for source cells and 0 for regular cells, compute for every cell the shortest 4-directional distance to any source ce...
Implement FizzBuzz
Implement the classic FizzBuzz problem. Given a positive integer n, return the sequence from 1 to n as strings with the following rules: - If a number...
Build a Local URL Shortener
Implement a local URL shortener that runs on a single machine. Design a small library or service with two core operations: - shorten(long_url) -> shor...
Reverse Linked List Groups
Given the head of a singly linked list and a positive integer k, reverse the list in consecutive groups of size k. Unlike the common variant where a f...
Implement an Arithmetic Expression Evaluator
Implement an arithmetic expression evaluator. Part 1: Given a string expression containing non-negative integers, spaces, and the operators '+', '-', ...
Implement a Time-Aware Task Manager
Design and implement an in-memory task management component. Each task belongs to one user. A task has a unique task ID, arbitrary task content, a cre...
Implement a hierarchical file store
Implement a simplified in-memory file store. The store uses absolute Unix-style paths such as /, /docs, and /docs/readme.txt. A path component contain...