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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"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."
Solve Morse and Network Access Tasks
Solve the following two independent coding problems. Problem 1: Convert Between Text and Morse Code You are given the standard Morse-code mapping for ...
Find Containing Range
This question evaluates the ability to design appropriate data structures and apply algorithmic reasoning for efficient interval containment queries, ...
Explain algorithm strategies and complexity
Explain algorithm strategies and complexity You are faced with a complex, potentially ambiguous coding problem. Describe how you would clarify require...
Evaluate Piecewise Linear Function
This question evaluates understanding of piecewise linear interpolation, numerical reasoning, and the ability to handle ordered 2D point data and edge...
Return Binary Tree Nodes in Vertical Order
Return Binary Tree Nodes in Vertical Order A binary tree has nodes numbered from 0 through n - 1, with node 0 as the root. Arrays left and right conta...
Merge Three Sorted Arrays Without Duplicates
Merge Three Sorted Arrays Without Duplicates You are given three integer arrays sorted in nondecreasing order. Merge them into one sorted array that c...
Implement A* Maze Search
Implement maze pathfinding in C++. You are given an m x n grid where '.' is an open cell, '#' is a wall, S is the start, and T is the target. You may ...
Streaming Entropy with Numerical Stability
This question tests a candidate's ability to implement numerically stable online algorithms for computing Shannon entropy over streaming data. It eval...
Reverse Nodes in K-Sized Groups
This question evaluates skills in manipulating singly linked lists, pointer reassignments, and performing in-place group transformations while meeting...
Propagate runtime ID across API requests
This question evaluates proficiency in runtime ID propagation across HTTP requests, JSON parsing and serialization, nested data traversal, and type-pr...
Find Maximum Unique-Character Subset
This question evaluates algorithm design and combinatorial optimization skills, specifically the ability to model disjoint-character constraints, hand...
Extend a Maze Solver
This question evaluates competence in graph search and state-space modeling, specifically BFS-based pathfinding, constrained traversal rules (directio...
Design a data structure for dynamic top‑K frequency
Design a data structure that maintains a multiset of integers and supports the following operations efficiently: Operations - insert(x): Add one occur...
Find top-k distinct elements
This question evaluates understanding of algorithms and data structures for selecting distinct top-k values and enforcing ordering constraints. It is ...
Reverse last two characters with space
This question evaluates basic string manipulation and character indexing skills, including handling of edge cases when treating input as a raw charact...
Flatten and unflatten nested Python structures
This question evaluates proficiency in manipulating nested data structures, deterministic traversal and mapping between hierarchical shapes and flat i...
Design rolling-window conversation score tracker
This question evaluates a candidate's ability to design efficient data structures and algorithms for time-windowed streaming data, including maintaini...
Design KV store with sliding-window average QPS
Problem Design an in-memory key–value store that supports mutation operations and can report the average QPS (queries per second) over a recent time w...
Design robust group size limiting for calls
Design the admission-control and enforcement algorithm to limit group-call size under real-world race conditions. Constraints: multiple SFU edges in m...
Implement streaming SRM detector with late events
Implement a streaming detector for sample ratio mismatch (SRM) across many concurrent experiments. Input is two topic-partitioned streams: assignments...