Coding & Algorithms Interview Questions
Practice 3,429 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."
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"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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"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 max min-plus-max over all subarrays
Find max min-plus-max over all subarrays You are given an array arr of n integers. A subarray is a contiguous non-empty segment of the array. For any ...
Design event timeout detector
Design and implement an event-timeout detector for a job scheduler. Inputs: a global timeout T and a stream of events; each event has {event_id, type ...
Validate normalized palindromes with variants
Implement a function isNormalizedPalindrome(s) that returns true if s reads the same forward and backward after removing non‑alphanumeric characters a...
Implement a simplified multi-level banking system
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Solve three mini-game algorithm tasks
Solve three mini-game algorithm tasks Solve three mini-game algorithm tasks: (a) Move-House Puzzle: Given initial and target arrangements of N labeled...
Compute nearest dashmart and busiest assignments
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Implement string sum and weighted city picker
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Identify and prevent code-breaking inputs
Identify and prevent code-breaking inputs Identify inputs and scenarios that could break your implementation and explain how you would prevent them. C...
Solve snake game, peak search, and task scheduling
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Parse chemical formula with multipliers
Parse chemical formula with multipliers Given a string representing a chemical formula, parse it and return the total count of each element. The formu...
Solve library coding tasks in Python
Solve library coding tasks in Python Implement the following Python tasks: 1) Given a list of (category, points) for books, choose up to 3 books with ...
Compute build order from dependencies
Compute build order from dependencies You are given a directed graph represented as a mapping where each key X maps to a list of tasks that depend on ...
Detect currency arbitrage with costs
You are given a K×K matrix R of currency exchange rates where R[i][j] is the amount of currency j obtainable for one unit of currency i, and R[i][i] =...
Design refundable transaction ledger and prioritization rules
Design and implement a transaction ledger that ingests a stream of records where each record is either a payment or a refund. Each payment has {id, us...
Implement Markdown-to-HTML parser
Implement a function that converts a plain-text string into HTML supporting only these features: ( 1) Paragraphs: two or more consecutive newline char...
Count decodings of a digit string
Count decodings of a digit string You are given a non-empty digit string s consisting of characters '0'–'9' and a mapping where 1->'a', 2->'b', ..., 2...
Group anagrams and count string in grid
Part 1 — Group Anagrams: Given an array of strings, group together strings that are anagrams of one another and output both the grouped lists and the ...
Implement range-sum tree and sort merged lists
Implement range-sum tree and sort merged lists 1) Given a binary tree whose nodes store integer values, and two integers low and high defining an incl...
Implement sparse vector dot product and cosine similarity
Sparse Vector Class Implement a SparseVector class for high-dimensional vectors where most entries are zero. Representation Assume each vector has: - ...