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."
Count interval intersections
Question For a list of n segments, where each segment i has start[i] and end[i], compute for every segment the count of other segments that intersect ...
Recommend friends-of-friends
Question Given a dictionary such as {A:[B,C], B:[C,D], C:[E]}, return for a user U all people followed by U’s followees but not already followed by U....
Compute delay times in priority array
Question Given an array of integers representing task priorities processed from right to left, return an array where each element is the distance (ind...
Validate carpool capacity
Question LeetCode 1094. Car Pooling – Given trips[i] = [numPassengers, start, end] and an integer capacity, return true if the vehicle can fulfill all...
Compute minimum delivery days
Question Given N distribution centers numbered 1..N and an orderCityList of length M where orderCityList[i] denotes the city that the i-th order must ...
Implement rate limiter, top-K, scheduler algorithms
Question Design and implement a thread-safe Rate Limiter; extend it to support multi-threading and a version where current time is not passed as an ar...
Implement bank balance operations
Question Design and implement a Bank account class that supports the operations Deposit(amount), Withdraw(amount), and CashBack(percent). Ensure balan...
Compute drawdown, profit, and coin change
Question What is the maximum drawdown of a cumulative PnL (profit and loss) series, and when did it occur? Implement a function mdd(pnl) that returns ...
Find concatenated words in list
Question LeetCode 472. Concatenated Words – Given an array of strings words, return all words that are concatenations of at least two shorter words al...
Solve Search Insert Position Using Binary Search
Scenario Live coding round for an Amazon Applied Scientist position; candidate must solve LeetCode 35 (Search Insert Position) without helper librarie...
Solve 15 common interview problems
Below are fifteen independent coding problems commonly discussed in software engineering interviews. For each one, write an efficient algorithm and be...
Design payment scheduler with cancel and top-K outgoing
Design and implement an in-memory banking payment component with the following APIs: ( 1) schedulePayment(payerId, payeeId, amount, executeAt) -> paym...
Compute maximum perimeter among islands
Problem You are given an m x n binary grid grid where: - grid[r][c] = 1 represents land - grid[r][c] = 0 represents water An island is a maximal set o...
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...
Implement Connect Four with win detection
Implement a Connect Four game engine. Support a general m×n board (default 6× 7) and a win condition of k in a row (default 4). Provide an API: Connec...
Merge overlapping time intervals efficiently
Given a list of closed intervals [start, end] with 0 <= start <= end, merge all intervals that overlap or touch and return a minimal set of non-overla...
Solve matrix diagonal and sliding-window statistics
1) Given an m x n integer matrix, determine whether every top-left to bottom-right diagonal has the same value (Toeplitz property). Return true/false,...
Check diagonal equality in a matrix
Given an m x n integer matrix, determine whether every top-left to bottom-right diagonal contains identical values (all elements along each such diago...
Solve concurrency in Java
How do you handle concurrency in Java? Compare threads, the Executor framework, synchronized blocks, explicit locks, atomic variables, concurrent coll...
Compute sliding-window medians
Given an array nums and an integer k, compute the median for each contiguous subarray (window) of length k and return the sequence of medians in order...