Coding & Algorithms Interview Questions
Practice 3,013 real Coding & Algorithms interview questions for 2026. Coding & Algorithms interview questions for top tech firms like Meta, Amazon, Google, Uber, and TikTok — real questions from actual interviews with detailed solutions — to power your interview preparation. This collection is sharply focused on algorithmic patterns (arrays, strings, sliding windows, trees/graphs, dynamic programming, greedy, two-pointers, and hashing), clean, review-ready code, and the explanation skills that distinguish hires. In 2026 expect familiar medium-to-hard problems plus newer twists: AI-enabled or multi-file coding rounds at some companies, more emphasis on explainability and edge-case reasoning, and occasional real-world performance constraints (streaming, concurrency, memory limits). Interviewers evaluate problem framing, algorithm choice, complexity trade-offs, test-case thinking, and communication under time pressure. Best prep mixes pattern-based practice, timed mock interviews, code-review style polishing, and rehearsed explanations of complexity and tradeoffs. Focus your last-mile prep on writing correct, readable code quickly and on explaining why your solution is robust and efficient for production scenarios.
"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."
Generate primes up to n efficiently
Implement a function that returns all prime numbers in the inclusive range 1..n. Requirements: handle n up to 10^7 efficiently (time and memory); retu...
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. (...
Compute max island with constrained flips
Given an n×n binary grid G where 1=land and 0=water with 4-directional connectivity, return the size of the largest island achievable by flipping at m...
Compute binary-tree diameter via return-only DFS
Given the root of a binary tree, compute its diameter defined as the number of edges on the longest path between any two nodes. Implement a DFS that r...
Implement list overlap and dense-ranked word frequencies
Part A — Multiset overlap count Implement count_overlap(a: List[int], b: List[int]) -> int that returns the size of the multiset intersection of a and...
Design Tic-Tac-Toe and QPS data structures
You are given two independent coding problems that focus on data structure and API design. --- Problem 1: Generalized Tic-Tac-Toe Game with Simple AI ...
Compute courier pay and implement load balancing
Problem 1: Compute courier (delivery driver) pay You are given a sequence of delivery-related events for a courier during a day. Your task is to compu...
Implement Parallel Image Processing
Build an image-processing utility in Python using the Pillow library. You are given a collection of image file paths and an output directory. For each...
Implement a Referral Revenue Tracker
Implement an in-memory revenue tracking system for customers in a referral network. Each customer has their own direct revenue. A customer may also ha...
Find Maximum Window Sum
Given an integer array nums and an integer k, write code to find the maximum sum of any contiguous subarray of length exactly k. Assume 1 <= k <= len(...
Compute nested depth sum and grid distance
Problem A: Weighted sum of integers in a nested list You are given a nested list structure that may contain integers or other nested lists. Define the...
Merge overlapping time intervals
Problem You are given a list of closed intervals intervals, where each interval is [start, end] and start <= end. Merge all intervals that overlap and...
Implement an in-memory SQL-like table
Problem Implement a simple in-memory database for one table. All values are strings. Each row is identified by a rowKey (string). Each row contains co...
Solve Time-Window and Binary Swap Problems
This online assessment contained two coding problems: 1. Maximum requests in a time window You are given a non-decreasing integer array requestTimes...
Determine dictionary-based string segmentation
You are given a string s and a set of tokens dict. Determine whether s can be segmented into a sequence of one or more tokens from dict. If segmentati...
Find all balanced k in a permutation
You are given a permutation \(p\) of length \(n\) containing each integer from \(1\) to \(n\) exactly once. For each \(k\) where \(1 \le k \le n\), de...
Find accessible devices via nested memberships
Problem You are given an access model with nested groups: - A group can contain users and also contain other groups (subgroups). - A user can own or b...
Rebalance shard ranges under overlap limit
You maintain a set of data shards. Each shard owns an inclusive integer key range [start, end]. `python class Shard: id: str start: int en...
Solve three coding rounds
You are given three independent interview-style coding tasks. 1) Nearest cake/person in a 2D grid You are given an m x n grid of integers: - 1 = cake ...
Simulate meeting-room bookings and return busiest room
You manage n meeting rooms labeled 0..n-1 and receive a list of meetings. Each meeting is an interval [start, end) with start < end. Process meetings ...