Coding & Algorithms Interview Questions
Practice 3,469 real Coding & Algorithms interview questions for 2026. Covers companies like Meta, Amazon, Google, Uber, and Microsoft. Real questions from actual interviews with detailed solutions — ideal for focused interview preparation. Coding & Algorithms interview questions are the single most common technical gate for software engineering roles and are used to evaluate problem framing, algorithm selection, complexity trade-offs, correctness, edge-case reasoning, and clear communication under time pressure. Expect this category to appear in early technical screens and repeatedly across onsite loops at companies that weight it heavily (notably Meta, Google, and Amazon). Interviews will test arrays and strings, trees and graphs, dynamic programming, hashing and two‑pointer techniques, and the candidate’s ability to test and optimize code in a shared editor. Prepare with timed mock interviews, practice in the same editor you’ll use live, and build a progressive schedule that moves from fundamentals to medium/hard problems; typical candidates invest several weeks to a few months of focused practice depending on seniority and target company.
"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."
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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."
Compute time to burn tree
Given the root of a binary tree and the value of a target node that starts burning at time 0, fire spreads every minute from a burning node to its lef...
Compute Minimum Production Days
Question You are given a list of product IDs products, where products[i] is the type of the product that must be produced at step i, and a non-negativ...
Build a Tic-Tac-Toe App
Implement a simple Tic-Tac-Toe mobile app that can be completed in a 45-minute coding interview. Requirements: - Display a 3x3 board. - Support two lo...
Implement Connect Four Winner Detection
Implement a Connect Four-style game engine. The board has 6 rows and 7 columns. Two players alternate turns. On each turn, the current player chooses ...
Generate combinations and permutations
This question evaluates a candidate's ability to implement combinatorial generation of combinations and permutations using distinct elements, testing ...
Find length of longest common subsequence
This question evaluates understanding of dynamic programming, string algorithms, and algorithmic problem-solving skills related to sequence comparison...
Maximize minimum value after k decrements
This question evaluates array-based optimization skills, resource-allocation reasoning under a fixed decrement budget, and algorithmic complexity anal...
Find two numbers summing to target without hashmap
This question evaluates array manipulation, index-tracking, and algorithmic problem-solving skills, with emphasis on time and space complexity trade-o...
Decode a password string into letters
This question evaluates string parsing and encoding/decoding skills, specifically mapping numeric tokens and handling delimiter characters within the ...
Find when failures started in log stream
This question evaluates understanding of monotonic sequences and search algorithms (such as binary search), along with algorithmic reasoning about cor...
Compute nearest gate distance in grid
This question evaluates grid traversal, distance propagation, obstacle handling, and in-place matrix update competencies within the Coding & Algorithm...
Implement array and tree traversal tasks
This question evaluates algorithmic problem-solving and data-structure competency, specifically array-based optimization for single-trade profit and t...
Scale Game of Life to huge matrices
This question evaluates a candidate's ability to design space-efficient, I/O-aware algorithms and streaming or external-memory techniques for processi...
Validate JSON against a protobuf-like schema
This question evaluates schema validation and data-typing skills, including understanding of JSON primitive types, recursive message structures, and c...
Flatten a nested JSON object
This question evaluates the ability to traverse and manipulate nested JSON-like structures, emphasizing concepts such as recursion or iterative traver...
Compute reachable cells for a cleaning robot
This question evaluates understanding of graph traversal, state-space modeling, and scalability when computing reachable cells on a 2D grid under 8-di...
Return all files under a path
This question evaluates filesystem traversal and recursive/iterative algorithm skills, including handling different path types, edge cases such as mis...
Generate all hyperparameter combinations
This question evaluates competence in combinatorial enumeration and manipulation of data structures for generating hyperparameter configurations, test...
Find earliest time all riders become connected
This question evaluates graph connectivity and dynamic event-processing skills, testing conceptual understanding of connectivity in undirected graphs ...
Find kth element and sliding-window kth in stream
This question evaluates understanding of order statistics and selection in arrays as well as sliding-window stream processing, including maintaining k...