Coding & Algorithms Interview Questions
Practice 2,960 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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"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 stream line reader and settle balances
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Group employees by shared interests
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Compute max coins with 3-step token moves
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Compute reachable cells for a cleaning robot
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Implement multi-level task manager APIs
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Match Bookings to Payments
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Compute and plot a precision–recall curve
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Solve Three Coding Interview Problems
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Find linked merchants by shared fields
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Maximize sum without choosing adjacent elements
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Return all combinations that sum to target
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Implement an LRU cache
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Implement a Composable Event Recommendation Engine
Design and implement a flexible event recommendation engine in Java. You are given domain objects such as Event, Customer, Inventory, and a LocationSe...
Implement a high-throughput web crawler safely
Design and code (pseudocode acceptable) a multi-threaded web crawler that favors breadth-first discovery while continuously running analysis tasks on ...
Implement lazy unique-merge generator for sorted streams
Write a Python generator merge_unique(a, b) that lazily merges two nondecreasing iterables a and b (potentially infinite) into a single nondecreasing ...
Find list pair with maximum overlap
You are given N labeled lists of items as a Python dict mapping list_name -> iterable of strings. Example input: {'L1': ['A','B','C'], 'L2': ['A','C',...
Reverse a list in-place
Coding Task: Reverse a List In-Place (Python) Context You're implementing a utility function during a technical screen. The function must reverse a Py...
Find gaps between intervals
You are given a list of integer intervals intervals, where each interval is represented as [start, end] (inclusive), and start <= end. Two intervals m...
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...
Count Same-Day Registered Posters
You are given two tables: `text users - user_id: unique identifier for a user - registered_at: timestamp when the user registered posts - post_id: uni...