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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"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."
Count subarrays with sum equals k
This question evaluates a candidate's competency in array algorithms and reasoning about contiguous subarray sums, including correct handling of negat...
Answer suffix maximum-frequency queries
This question evaluates algorithm design skills and array-processing competency for answering repeated queries efficiently, focusing on time and space...
Determine escape path with blockers and spreading fire
This question evaluates graph traversal and grid-based pathfinding skills, including connectivity analysis, obstacle handling, and reasoning about tim...
Find bounding boxes of connected houses
This question evaluates grid traversal and connected-component identification skills, specifically handling ragged 2D arrays, 4-directional adjacency,...
Compute sparse dot product and count islands
You are asked to solve two coding problems. Problem 1: Sparse vector dot product Given two vectors A and B of the same length n (potentially large, e....
Implement a resumable data loader
This question evaluates a candidate's ability to design stateful, resumable data iteration with deterministic shuffling and compact serializable check...
Implement a fixed-capacity generic circular buffer
This question evaluates knowledge of data structure design, generic types, in-place memory allocation, and constant-time FIFO operations required for ...
Implement a single-thread task scheduler API
This question evaluates understanding of task scheduling, timing semantics, deterministic ordering, single-thread concurrency control, and data struct...
Compress vertices into uniques and indices
This question evaluates a candidate's ability to perform duplicate detection and compression of sequences of fixed-length tuples, exercising skills in...
Compute ETA between two map nodes
This question evaluates proficiency in graph algorithms and shortest-path computation, specifically handling weighted directed graphs, non-negative tr...
Merge intervals and design rating APIs
This question evaluates algorithmic problem-solving for interval manipulation and stateful data-structure design for maintaining and ordering agent av...
Compute inverse-depth weighted sum of nested lists
Inverse-Depth Weighted Sum of a Nested List You are given a nested list of integers. Each element is either: - an integer, or - another nested list. D...
Find the longest palindromic substring
Problem Given a string s, find the longest contiguous substring of s that is a palindrome (reads the same forward and backward). Input - A string s co...
Implement 2048 tilt move
Problem: Implement a 2048 “tilt” (move) operation You are given a 4×4 board for the game 2048. Each cell contains either 0 (empty) or a power of two (...
Decompress encoded string with nested repeats
This question evaluates string parsing and manipulation skills, particularly handling nested repetition encodings and reasoning about output growth, a...
Select transactions to maximize fees under size
This question evaluates the ability to model and optimize resource allocation under capacity constraints, testing algorithmic skills in dynamic progra...
Find user who can access every camera
This question evaluates reasoning about access-control and transitive relationships, testing skills in graph modeling, reachability, and set operation...
Compute maximum later-earlier difference
This question evaluates array-processing and algorithmic optimization skills, testing reasoning about element relationships in sequences; it falls und...
Find minimum threshold enabling grid path
This question evaluates a candidate's understanding of grid pathfinding, reachability under constraints, and algorithmic optimization, focusing on ski...
Count White Balls After K Steps
You are given a ring of N positions indexed from 0 to N-1. - At each position i, there is initially one ball whose color is either white or black. - E...