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."
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"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."
Implement Card Validation and Recovery System
Question Design and implement a payment-card validation system supporting: Basic VISA validation (16-digit numbers starting with 4) using the Luhn che...
Find earliest supporting dependency version
Question Given a list of dependency versions (e.g. [103.003.02, 103.003.03, 203.003.02]) and a black-box API isSupported(v), design an algorithm to fi...
Compute drawdown, profit, and coin change
Question What is the maximum drawdown of a cumulative PnL (profit and loss) series, and when did it occur? Implement a function mdd(pnl) that returns ...
Implement bank balance operations
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Solve weighted pick and product except self
Question LeetCode 528. Random Pick with Weight LeetCode 238. Product of Array Except Self https://leetcode.com/problems/random-pick-with-weight/descri...
Solve non-repeating show substring
Question LeetCode 3. Longest Substring Without Repeating Characters – variant where the elements are show names instead of numbers. https://leetcode.c...
Maximize path score in DAG
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Validate carpool capacity
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Implement rate limiter, top-K, scheduler algorithms
Question Design and implement a thread-safe Rate Limiter; extend it to support multi-threading and a version where current time is not passed as an ar...
Implement portfolio optimization simulation
Question Given price-return time series in a DataFrame, simulate random portfolio weights, compute expected return, volatility, Sharpe ratio, and retu...
Optimize file reading and expression DFS
Optimize file reading and expression DFS Given a large password file, build a program to read the required password(s) while minimizing memory usage. ...
Find concatenated words in list
Question LeetCode 472. Concatenated Words – Given an array of strings words, return all words that are concatenations of at least two shorter words al...
Count subarrays summing to target
Question LeetCode 560. Subarray Sum Equals K – Given an integer array nums and an integer k, return the total number of continuous subarrays whose sum...
Compute balances and array queries
Question Given a list of transactions where each transaction has a userId and an amount (positive for credit, negative for debit), compute the final b...
Solve Number of Islands
Question LeetCode 200. Number of Islands – Given a 2D grid of '1's (land) and '0's (water), count the number of islands. Follow-up: implement the solu...
Solve string match and DashMart BFS
Question Implement a string-matching function that returns the first index of a pattern in a text (akin to LeetCode 28 Implement strStr()). 2) “Dash M...
Compute immediate delivery percentage
Compute immediate delivery percentage LeetCode 1173. Immediate Food Delivery I – Write an SQL query to calculate the percentage of immediate (same-day...
Check diagonal and compute window statistics
Question Given a square matrix, determine whether all elements on its main diagonal are identical. LeetCode 346. Moving Average from Data Stream – des...
Design test-run logging and query functions
Question Implement log(test_id, timestamp, status) to record a test run, where timestamps are strictly increasing across all test IDs. Implement get_m...
Implement Cosine Similarity Function for String Vectors
Scenario Technical phone screen in Python; assess ability to implement similarity metric. Question Implement a Python function that computes the cosin...