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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"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."
Detect Fraud by Propagating Suspicious PII
Detect Fraud by Propagating Suspicious PII Process a stream of underwriting and fraud_flag events in order. Maintain a set of suspicious PII values dr...
Count Distinct PII in Underwriting Events
Count Distinct PII in Underwriting Events An event stream contains underwriting and fraud_flag events. Count the distinct nonempty personally identifi...
Solve interval, grid-fill, and heap tasks
You are asked to solve the following algorithmic problems. Problem 1: Concurrent users from online intervals You are given n inclusive time intervals ...
Return Unique Three-Sum Value Triples
Return Unique Three-Sum Value Triples Problem Implement threeSumTarget(nums, target) -> triples. Return every distinct value triple [a, b, c] for whic...
Generate a Matrix in Spiral Order
This question evaluates a candidate's ability to simulate array traversal and manage boundary conditions when filling a matrix in a specific geometric...
Compute and plot a precision–recall curve
You are given model outputs for a binary classifier: - y_true: an array of 0/1 ground-truth labels of length n. - y_score: an array of predicted score...
Implement in-memory data structures and booking API
This question evaluates proficiency in data structures and algorithms, systems-level data modeling, and practical API design by testing in-memory key-...
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...
Write SQL to rank top products per category
You are given two tables: products - product_id (int, primary key) - category (string) order_items - order_id (int) - product_id (int) - quantity (int...
Generate all strings by expanding wildcards
Problem Given a string s consisting only of characters '0', '1', and '', replace every '' with either '0' or '1' and return all possible resulting bin...
Return all root-to-leaf tree paths
Given the root of a binary tree, return all root-to-leaf paths. - A leaf is a node with no children. - A path should be represented as a string with n...
Reverse linked lists, including k-group
Singly Linked List Reversal — Variants and Edge Cases You are given a standard singly linked list with nodes of the form: - Node fields: value, next -...
Implement Stable Softmax
This question evaluates understanding of numerical stability, floating-point arithmetic, normalization, and probability distributions when computing s...
Implement Persistent Memoization LRU Cache
This question evaluates knowledge of memoization, LRU cache semantics, deterministic cache-key construction from positional and keyword arguments, JSO...
Compute Roller Coaster Scores
This question evaluates proficiency in string parsing, floating-point arithmetic, conditional logic, and designing extensible rule-based scoring syste...
Implement SFT Sample Packing
This question evaluates proficiency in preprocessing for autoregressive language models, including deterministic sequence packing, construction of los...
Find Minimum Compatible Version
This question evaluates binary search, monotonic predicates, careful version ordering, and cost-aware optimization of expensive compatibility checks. ...
Return Elements Greater Than the Overall Average
Return Elements Greater Than the Overall Average Implement above_average(values). Compute the arithmetic mean of the entire non-empty integer list, th...
Determine Redeemable Promotion Offers
This question evaluates proficiency in event-stream processing, stateful counting, timestamp filtering, and enforcing business constraints for limited...
Find shared courses between student pairs
This problem set evaluates data structures and algorithms competencies, covering mapping and set intersection for pairwise course overlap, permutation...