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."
"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."
"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."
"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 maximum later-earlier difference
This question evaluates array-processing and algorithmic optimization skills, testing reasoning about element relationships in sequences; it falls und...
Design a scalable URL shortener
Design a highly scalable URL shortening service, similar to Bitly or TinyURL. The service converts long URLs into short links and redirects short-code...
Weighted Random Sampling by Index
Weighted Random Sampling by Index You are given an array of positive integer weights weights, where weights[i] is the weight assigned to index i. Impl...
Count queen attacks on points with blockers
You are given positions on an (unbounded) 2D integer grid. - queens: coordinates of queens - points: query coordinates A queen attacks along 8 directi...
Validate whether a binary string is good
You are given a binary string s consisting only of characters '0' and '1'. Define a good string recursively by the grammar: - '0' is a good string. - ...
Solve array merge, tree view, and maze tasks
This question evaluates array manipulation and in-place algorithms, binary tree traversal and visibility reasoning, and grid graph traversal for path ...
Compute party time blocks per neighborhood
You are given two datasets: 1. Parties: - party_id (string or integer) - start_timestamp (e.g., UNIX timestamp or datetime) - end_timestamp (...
Implement a rate-limited hit counter
You are designing a hit counter that records the number of hits received in the past 5 minutes. Implement a class HitCounter with the following method...
Design crypto trading order control API
You are implementing part of a simple crypto trading system that manages client orders. Each order can be in one of several states: NEW, ACTIVE, PAUSE...
Identify trees, lists, and array search costs
Answer all parts concisely and justify time complexities. a) A data model requires each node to have at most two children and a single parent. Name th...
Detect k events in a sliding window
Implement an algorithm that, for each user, determines whether there exists a set of at least k ACH credit events from distinct device_ids within any ...
Prove reservoir sampling correctness
Design an algorithm to sample k items uniformly at random from a stream of unknown and potentially massive length N, using O(k) memory and one pass. (...
Print Sentences as Table
Implement a function that formats a list of sentences as a bordered table. Given: - sentences: a list of strings - width: the fixed content width of e...
Track Highest-Earning Experience
You are building a core component for a real-time analytics system that tracks the profitability of experiences on a large online platform. Implement ...
Design a data structure to find streaming median
This question evaluates proficiency in data structure and streaming algorithm design for maintaining the median of a dynamic integer stream, testing c...
Parse API JSON and print org chart
You will solve two practical coding tasks. Task 1: Call an HTTP API and parse JSON You are given an HTTP endpoint that returns JSON describing transit...
Solve Adjacent-Deletion and Sorted-Square Problems
Solve the following coding problems. Discuss the approach and complexity before implementation. Problem 1: Remove adjacent duplicate pairs Given a str...
Place Pieces on a Grid
Given integers n and m, and an ordered list figures where each element is one of "A", "B", "C", "D", or "E", construct an n x m integer matrix grid. T...
Extend a Maze Solver
This question evaluates proficiency in implementing and debugging graph search algorithms and state-space modeling, including correct visited-state ha...
Implement encryption and constant-time random set
This question evaluates understanding of symmetric shared-secret string transformation and the design of a randomized set supporting expected O(1) ope...