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.

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"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."

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"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."
Implement Plus One
Given an integer represented as an array of digits digits, where the most significant digit comes first, return the array representing the integer plu...
Find Valid IP Addresses in Files
You are given an absolute or relative path to a directory on the local file system. Write a program that recursively traverses every subdirectory unde...
Simulate a Rank-Based Tournament
You are given an array ranks, where ranks[i] is the rank of player i in the initial bracket order. A smaller rank value means a stronger player. The t...
Merge Overlapping Intervals
Merge Overlapping Intervals You are given an array intervals where each element intervals[i] = [start_i, end_i] represents a closed interval on the nu...
Shift Non-Zero Elements Left In Place
Shift Non-Zero Elements Left In Place You are given an integer array nums. Rearrange the array in place so that every element equal to 0 is moved to t...
Implement crawler, dedup, and persistent LRU
Question LeetCode 1236. Web Crawler: Crawl web pages starting from a given URL within the same hostname. LeetCode 609. Find Duplicate File in System: ...
Return Top Department Suggestions
You are given a static in-memory list of Suggestion objects loaded by a server: `text Suggestion { ngram: string, department: int, score: int } ...
Return Top K Open Businesses
You are given a list of business candidates. Each candidate has at least the following fields: - score: a numeric relevance score - distance: a numeri...
Solve Throughput, Rate Limiting, and LFU
The interview included the following coding tasks: 1. Minimum processing speed: You are given an array piles, where piles[i] is the size of the ith pi...
Compute transfers to balance account debts
Problem: Balance accounts by generating transfers You are given a dictionary/map balances from accountId -> netBalance. - A positive balance means the...
Find an Exit in a URL Maze
You are given a starting URL for a web-based maze. Each URL represents one room in the maze. Your task is to write a program that discovers whether th...
Solve Matrix Traversal and Pair Sum
You will solve two independent coding problems. Problem 1: Traverse a Matrix in Spiral Order Given an m x n matrix of integers, return all elements in...
Find linked user records by similarity
You are given a list of user records. Each record has the following fields: - id (integer, unique) - name (string) - email (string) - company (string)...

Implement Dependency-Aware Task Scheduler
Design and implement a task scheduler that supports adding tasks and consuming executable tasks in deadline order. Each task has: - taskId: a unique i...
Maximize block fee with transaction selection
You are given N transactions. Each transaction has: - id (unique identifier) - size (positive integer) - fee (positive integer) You are building a blo...
Merge overlapping corrections
Implement correctionMerge(corrections). You are given a list of text-correction spans. Each correction applies to an inclusive interval [start, end] a...
Compute distance to nearest taxi in grid
You are given an R x C grid representing a city map. - grid[r][c] = 1 means there is a taxi located at cell (r, c). - grid[r][c] = 0 means the cell is...
Reconstruct route from unordered travel tickets
You are given a list of directed travel tickets, each represented as a pair [from, to] (city names are strings), e.g. [["A","B"],["B","C"], ...]. The ...
Implement a Referral Network
Implement a referral network in three parts. You are building an in-memory model of a directed referral graph. An edge A -> B means user A referred us...
Implement an in-memory SQL-like table
Implement a simplified in-memory SQL-like database for a single table. You should support the following operations on a table with a fixed schema (a l...