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."
"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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"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."
Determine whether two nodes are related
This question evaluates understanding of graph representations, reachability and connectivity concepts for ancestry relationships, including handling ...
Solve three string/stack/backtracking problems
This set evaluates proficiency with algorithmic patterns—stack-based and monotonic-stack reasoning for visibility problems, backtracking for combinato...
Solve tiling, probability, and nested-radical puzzles
This multi-part question evaluates combinatorics and algorithmic skills through 2×N and 3×N domino tiling problems, analysis of an infinite nested squ...
Determine whether a word exists in a letter grid
This question evaluates algorithmic problem-solving and implementation skills in grid-based search, including concepts like graph traversal and backtr...
Implement a thread-safe high-concurrency LRU cache
This question evaluates understanding of concurrent data structures, synchronization strategies, and LRU cache semantics within the Coding & Algorithm...
Count connected components in a binary grid
This question evaluates understanding of graph traversal and connected-components detection on a 2D grid, measuring the ability to model grid cells as...
Maximize profit from one stock trade
This question evaluates algorithmic problem-solving skills with emphasis on array processing, numeric optimization, and time/space complexity analysis...
Group strings that are anagrams
This question evaluates skills in string manipulation, grouping by character composition, and the use of hashing or sorting techniques to construct ke...
Dedupe titles in per-shelf viewport
You are rendering a streaming app home page. - The home page consists of shelves displayed from top to bottom. - Each shelf contains a list of titleId...
Detect overlap of two linked lists with cycles
This question evaluates understanding of linked list data structures, cycle detection techniques, pointer/reference identity, and algorithmic time/spa...
Validate password and list rule violations
Problem You are given a password string p. Validate it against a set of rules and return all rules that the password violates. Rules 1. Length must be...
Minimize total distance to a store
Question 1: Choose a CVS location to minimize total distance You are given an M x N grid grid containing only 0 and 1. - grid[r][c] = 1 means there is...
Remove Repeated Character Groups
You are given a string s and an integer k. Repeatedly remove any contiguous group of k identical characters. After a removal, the remaining parts of t...
Implement Social Graph Snapshot Queries
This question evaluates understanding of graph data structures, query-efficient indexing, and algorithmic trade-offs for static directed graphs, inclu...
Process time intervals and detect overlaps/gaps
You are given n time intervals representing debug log segments. Each interval has a start time, an end time, and an associated text message. - Each in...
Return a valid task order
This question evaluates understanding of graph algorithms and dependency resolution, testing the ability to produce a valid ordering of tasks and reco...
Implement LRU cache and copy random list
This question evaluates competency in data-structure design, pointer and memory management, and hashing-based eviction policies by combining a deep-co...
Implement a Hierarchical File System
Implement an in-memory hierarchical file system. Create a class FileSystem with the following methods: - FileSystem() initializes an empty file system...
Implement one-cluster k-means
This question evaluates understanding of clustering algorithms and optimization of within-cluster squared error for the special case k = 1, along with...
Implement an LRU Cache
This question evaluates competency in designing efficient stateful data structures, understanding cache eviction policies (least recently used), and m...