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."
Design and Implement an LRU Cache
This question evaluates a candidate's ability to design and implement an LRU cache data structure with O(1) time complexity for both reads and writes....
Return the Vertical Traversal of a Binary Tree
Return the Vertical Traversal of a Binary Tree Problem Implement verticalTraversal(nodeValues, left, right, root) -> columns. Node root is at row 0, c...
Solve Wonderful Strings and Grid Queries
This question evaluates algorithm design and data-structure competencies through two problems: a parity-constrained minimum-cost string transformation...
Troubleshoot CPU, latency, and DNS issues
A) A Linux server’s CPU usage suddenly spikes. What immediate checks and commands would you run (e.g., top/htop, pidstat, perf, iostat), how would you...
Design receipt system with combo discounts
Question You are building a point-of-sale ordering UI for a food-ordering workflow. You are given class stubs and a callback you must wire up: - Item(...
Implement crawler and bracket validator
Implement two tasks: ( 1) Write a function crawl(start_urls, fetch, max_depth, domain_filter) that visits pages starting from the given seed URLs usin...
Evaluate a Boolean Formula AST
Evaluate a Boolean Formula AST Evaluate a formula represented as a JSON-compatible abstract syntax tree. A formula can contain Boolean literals, integ...
Implement a hierarchical file store
This question evaluates proficiency in modeling hierarchical file systems, path parsing and manipulation, managing mutable file contents, and analyzin...
Find Players with Uniquely Determined Rankings
Find Players with Uniquely Determined Rankings Problem There are n players numbered 0 through n - 1. Each result (winner, loser) states that the winne...
Infer and justify non-trivial sequence patterns
Pattern Recognition: Next Terms and Missing Value Identify the rule governing each sequence or row and compute the missing value(s). Justify each answ...
Implement CUDA-tiled matrix multiplication and explain architecture
CUDA FP32 GEMM Design Task Implement a high-performance CUDA kernel for matrix multiplication C = A · B where: - A is m×k, B is k×n, C is m×n - Data t...
Return the Most Frequent Integer with a Stable Tie-Breaker
Return the Most Frequent Integer with a Stable Tie-Breaker Given a nonempty integer array, return the value that appears most often. If several values...
Lane-Change Safety and Longitudinal Motion Simulation
This question tests practical application of kinematics, feedback control, and object-oriented design in a real-time simulation context. It evaluates ...
Compute the Diameter of an Undirected Tree
Compute the Diameter of an Undirected Tree You are given an undirected tree with nodes numbered from 0 through n - 1. The diameter is the number of ed...
Convert Valid Snake Case to Lower Camel Case
Convert Valid Snake Case to Lower Camel Case Given a valid snake-case identifier, convert it to lower camel case. The input consists of one or more lo...
Recover a Rooted Tree from Depth-Annotated Preorder
Recover a Rooted Tree from Depth-Annotated Preorder A rooted, ordered tree was serialized by preorder traversal. Before each node value, the serialize...
Implement ordering and undo executor
The interview included two coding tasks: 1. Dependency ordering: Given a set of tasks and their dependency relationships, return a valid execution ord...
Group words that map to same phone digits
Problem On a classic phone keypad (T9), letters map to digits: - 2: ABC, 3: DEF, 4: GHI, 5: JKL, - 6: MNO, 7: PQRS, 8: TUV, 9: WXYZ Given a list of lo...
Implement spreadsheet undo/redo operations
Problem Design a data structure that simulates Undo/Redo for a simplified spreadsheet editor. A user performs a sequence of operations on cells. Each ...
Test easy–medium array/string tasks
For typical easy–medium array and string problems, list the most important edge cases you would test (e.g., empty input, single element, duplicates, a...