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.
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"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 compressed vector and compute dot product
This question evaluates understanding of data structure design, sequence compression concepts (such as run-length patterns), and numeric algorithm eff...
Shortest Talent-Covering Team Starting At Each Index
There are n students in a line. Each student has exactly one talent represented by an integer from 1 to talentsCount. A valid team is a contiguous sub...
Merge Sorted Arrays
You are given two related tasks about sorted integer arrays. 1. Implement a function that takes two arrays sorted in nondecreasing order and returns a...
Implement a Transactional Key-Value Store
Design an in-memory key-value store that supports transactions. Required operations: - set(key, value): assign or overwrite the value for a key. - get...
Process Mutable Matrix Sum Queries
You are given a 2D integer matrix and a list of queries. There are two query types: - set r c v: update the value at row r and column c to v - get r1 ...
Convert State Stream to Events
This question evaluates a candidate's ability to process sequential categorical data by identifying and summarizing consecutive runs, reason about tim...
Implement a recency cache and min-coins DP
This question evaluates data structure design and algorithmic problem-solving skills, focusing on an LRU-style recency cache and a dynamic programming...
Compute infection spread time
This question evaluates understanding of grid-based graph traversal and propagation dynamics, testing competencies in breadth-first search concepts, s...
Implement a memory allocator with malloc/free
Problem You are implementing a simplified memory allocator over a contiguous memory region. Initialize the allocator with a fixed total size: - alloca...
Build a Weekly Calendar
Implement an interactive weekly calendar UI. Requirements: - Display a one-week calendar with 7 days. - The calendar should be divided into 1-hour tim...
Compute tree depth and meeting rooms
Solve both coding problems. Problem 1: Maximum depth of a binary tree Given the root of a binary tree, return its maximum depth. The maximum depth is ...
Solve Three Array Coding Problems
An online assessment contains the following three independent coding problems. For each problem, write a function that returns the requested value. Us...
Build a concurrent web crawler
This question evaluates understanding of concurrent programming, synchronization, thread safety, and graph traversal as applied to a multithreaded web...
Count Numbers Inside All Intervals
You are given: 1. An integer array nums. 2. A list of intervals intervals, where each interval is represented as [start, end]. The intervals are not s...
Compute longest common subsequence length
This question evaluates understanding of dynamic programming and sequence processing, measuring competence in reasoning about optimal substructure, ov...
Implement Nested Transactional Key-Value Store
Implement an in-memory key-value store that processes a batch of commands, one command per line. The store must support nested transactions. Supported...
Count numbers with same popcount up to all-ones bound
This question evaluates skill in bit manipulation and combinatorial counting over binary representations in the Coding & Algorithms domain, specifical...
Find all anagram start indices
This question evaluates proficiency in string manipulation, algorithmic efficiency, and pattern detection through character frequency analysis, assess...
Construct a circular gift exchange across families
This question evaluates ability to model constrained permutations and apply graph-theoretic and combinatorial reasoning to produce a single circular o...
Solve common search/parse/graph frequency tasks
This multi-part question evaluates algorithmic problem-solving skills across searching and sorting variants, rotated-array search, nested string decod...