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.
"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."
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"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."
Find shortest word transformation with caching
Find shortest word transformation with caching You are given a start word and an end word of equal length, and a dictionary of valid words. In one mov...
Compute total covered interval length
Compute total covered interval length Given a list of integer intervals [l, r) (half-open), compute the total length covered by at least one interval....
Maximize funds with capital-gated projects
Maximize funds with capital-gated projects You start with initial funds W and may undertake at most K projects. Each project i has a required capital ...
Compute build order from dependencies
Compute build order from dependencies You are given a directed graph represented as a mapping where each key X maps to a list of tasks that depend on ...
Compute sum of longest positive subarray
Compute sum of longest positive subarray Given an integer array that may contain positive and negative numbers, find the sum of the longest contiguous...
Design and implement Connect Four engine
Design and implement a Connect Four game engine. Use a default 6x7 board and two players. Provide an API with: drop(col, player) returning the row pla...
Count nonnegative buy/sell sequences
You must perform exactly 2n unit trades starting with 0 shares and ending with 0 shares. Each trade is either a buy (+1 share) or a sell (−1 share), a...
Compute minimal cost to merge numbers
Compute minimal cost to merge numbers Given an array of positive integers, you may repeatedly perform the following operation until one number remains...
Simulate robot on grid with obstacles
Simulate robot on grid with obstacles A robot starts at (0, 0) on an unbounded integer grid. You are given a sequence of commands consisting of charac...
Decide string transform with directional tokens and walls
Decide string transform with directional tokens and walls You are given two equal-length strings start and target of length n, each consisting only of...
Design a key-value store with getLast
Design a key-value store with getLast Design and implement an in-memory key–value store with this API: add(key, value), get(key), remove(key), and get...
Solve tree traversal and two-pointer problems
Solve tree traversal and two-pointer problems Implement the following independent problems: 1) Vertical columns: Given a binary tree, return lists of ...
Copy linked list with random pointers efficiently
Copy linked list with random pointers efficiently Given the head of a singly linked list where each node has next and random pointers, create a deep c...
Merge two sorted arrays in-place
Merge two sorted arrays in-place You are given two sorted integer arrays nums1 and nums2, both sorted in non-decreasing order. - nums1 has length m + ...
Maximize number with one digit swap
Maximize number with one digit swap Given a non-negative integer n (as an int or string), perform at most one swap of two digits to produce the maximu...
Validate word abbreviation and reconcile two abbreviations
Validate word abbreviation and reconcile two abbreviations Implement a function isValidAbbreviation(word: string, abbr: string) that returns true if a...
Find first unique character
Find first unique character Given a lowercase/uppercase alphanumeric string s, return the index of the first character that appears exactly once; if n...
Design Efficient Multi-Level Access Control System
Scenario Multi-level access control lists (country → city) must be queried quickly. Question Design and implement a permission system where each geogr...
Maximize Non-Overlapping Task Scheduling Efficiency
Scenario Job scheduler on a single machine wants to maximise throughput. Question Given tasks with [start, end) times, return the maximum number of no...
Implement Data Structure for Top-K Elements in Streams
Scenario Analytics feature that must constantly report the K largest numbers seen so far. Question Implement a data structure that ingests a stream of...