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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"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."
Format words into wrapped/justified lines
This question evaluates practical programming skills in string processing, greedy packing, and careful handling of spacing and edge cases, and falls u...
Compute time for virus to infect grid
This question evaluates a candidate's ability to reason about grid-based state propagation, algorithmic problem solving, and performance consideration...
Implement a versioned hash map with snapshot
VersionedHashMap (time-travel key-value store) Design and implement a data structure VersionedHashMap<K, V> backed by a hash map that supports retriev...
Answer two coding questions (SQL and DP)
This multi-part question evaluates SQL query skills (handling distinct values, aggregation and edge-case NULL results) and algorithmic proficiency in ...
Maximize sum with no adjacent elements
Given an array of non-negative integers nums, choose a subset of elements such that no two chosen elements are adjacent in the original array. Return ...
Find maximum collinear points
This question evaluates understanding of planar geometry and algorithmic reasoning for identifying collinearity, including handling duplicate points a...
Spell Out a Nonnegative Integer
Given a nonnegative integer, return its English words representation. Implement a function that handles numbers from 0 through 2,147,483,647 inclusive...
How to maximize rewards with exactly k tasks
You are assigning n independent tasks to two interns. - Each task must be done by exactly one intern. - If intern 1 does task i, you earn reward1[i] p...
Implement a sliding-window rate limiter allow()
This question evaluates understanding of sliding-window rate limiting, time-windowed counting, and per-user state management for high-throughput servi...
Compute total active time per Twitter Space
This question evaluates a candidate's ability to perform event-log sessionization and time-interval aggregation across users and spaces, testing skill...
Compute rainwater accumulation on a height grid
This question evaluates understanding of grid-based graph traversal, flow simulation to local minima, and the ability to reason about state propagatio...
Solve cache, grid path, and substring problems
This multipart question evaluates algorithmic problem-solving and data structure design skills, covering a capacity-bounded cache with eviction behavi...
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...
Find minimum-latency path across dependent services
This question evaluates understanding of graph algorithms and shortest-path computation on weighted directed graphs, including handling cycles, multip...
Detect stop tokens during streaming inference
This question evaluates streaming sequence-detection and pattern-matching skills, including online buffer management and correct handling of overlappi...
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 ...
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...
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...
Compute sums and maximum path in a tree
This question evaluates understanding and implementation of binary tree traversal, recursion, aggregation of node values, and computation of maximum s...
Compute iterative sliding-window sum reduction
This question evaluates algorithmic problem-solving and array-manipulation skills, focusing on sliding-window and iterative reduction concepts within ...