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."
Implement anagram check and stable deduplication
Part A — Anagram checker: Write a function is_anagram(a: str, b: str, locale: str = 'en') -> bool that returns True iff a and b are anagrams under the...
Debug and test a Python function in venv
Consider the Python snippet below. """ import math def accumulate(nums, start=0, cache={}): total = start for n in nums: if n % 2 == 0: nums.appen...
Implement streaming SRM detector with late events
Implement a streaming detector for sample ratio mismatch (SRM) across many concurrent experiments. Input is two topic-partitioned streams: assignments...
Implement piecewise linear interpolation for time-to-empty
Time-to-Empty from a Discharge Curve (Piecewise Linear Interpolation) Implement a function time_to_empty(checkpoints, current_soc) that returns the nu...
Implement sliding-window device anomaly
Streaming detection algorithm: Implement a function process_logins(stream) that consumes a time-ordered stream of login events (user_id, ts, device_id...
Implement K-means and run two iterations
Given points P={(0,0),(0,2),(2,0),(2,2),(8,8),(8,10),(10,8),(10,10)} and k=2, (1) initialize centroids with k-means++ using seed=42 and Euclidean dist...
Implement Director awards with Python OOP
Python OOP Exercise: Director extends Cast Context You are working with a simple class hierarchy where Director extends Cast. Implement a robust, test...
Solve substring and top‑K pair problems
Problem A: Smallest window containing all characters Given two strings s and t, find the shortest substring of s that contains all characters of t wit...
Find Duplicate Files
Implement a file deduplication tool. You are given a root directory containing many files. Return groups of duplicate files. Two files are duplicates ...
Implement weighted random city and sparse dot product
Question 1: Weighted random city picker You are given a mapping from city → population (all populations are positive integers). Implement a random gen...
Return all root-to-leaf path sums
Problem You are given the root of a binary tree where each node contains an integer value (may be negative). Return an array/list containing the sum o...
Implement TF-IDF scoring for documents
Problem Implement a simplified TF–IDF scorer. You are given: - A list of documents docs, where each document is a string. - A query string q. Tokeniza...

Compute party hours per town and city gaps
You are given (1) a region table describing a hierarchy of locations and (2) a list of party attendance time intervals (all timestamps occur within a ...
Implement web data fetch and storage tool
Problem You are asked to implement a small program that retrieves data from a remote web service protected by token-based authentication, parses the r...
Find Most Frequent Values
Given an integer array nums and an integer k, return the k distinct values that occur most frequently in nums. The result may be returned in any order...
Implement a generic tree Node class
Design and implement a Node class for a mutable rooted tree. Requirements: store value, parent, and ordered children; support add_child, remove, move_...
Parse a nested list from a string
Given a string that encodes a nested list (ArrayList-like notation), parse it into an in-memory nested list structure. Input format - The string conta...
Find Words Containing Other Words
Given a list of lowercase strings, return all words that contain at least one other distinct word from the same list as a contiguous substring. Exampl...
Generate NFT metadata and ensure uniqueness
You are implementing an NFT metadata generator. Each NFT is defined by selecting exactly one trait value from each trait category. You must generate a...
Compute total wages and partial-hour payments
You are given a list of workers. Each worker has: - id (string) - hourly_rate (non-negative number) - one work shift for a given day: start_time, end_...