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."
Determine if robot path is bounded
A robot starts at (0, 0) facing North on an infinite grid. It executes a string s consisting of 'G' (move forward 1 unit), 'L' (turn left 90°), and 'R...
Solve increasing sequence and path problems
Answer the following related tasks about increasing sequences and paths: a) Contiguous subarray: Given an integer array nums, find the longest strictl...
Count super-streak segments in an event stream
You are given a time-ordered sequence of events. Each event has: - type, a string or integer event type. - ts, an integer timestamp in milliseconds or...
Evaluate word-guess feedback with repeats
You are implementing feedback for a Wordle-like guessing game. Part 1 — Produce feedback for one guess You are given two strings of equal length guess...
Compute maximum score using up to 3 categories
Problem A library runs a summer reading program. Each book a student reads earns a certain number of points, and each book belongs to a category. A st...
Decompress an encoded string
Given an encoded string, return its decoded (decompressed) form. Use the following encoding rule: - A positive integer \(k\) followed by a bracketed s...
Sort a Nearly Sorted Array
Given an array nums of length n in which every element is at most k positions away from its location in the fully sorted order, return the array in so...
Implement dynamic batching for token decoding
You are given a black-box “simulated language model” interface that can advance many sequences in a batch. Model interface - Tokens are integers. - mo...
Find Shortest Knight Path
Given an N x N chessboard, a start cell (sr, sc), and a target cell (tr, tc), compute the minimum number of moves for a knight to reach the target. A ...
Identify and prevent code-breaking inputs
Identify inputs and scenarios that could break your implementation and explain how you would prevent them. Consider null or empty inputs, invalid dire...
Design event timeout detector
Design and implement an event-timeout detector for a job scheduler. Inputs: a global timeout T and a stream of events; each event has {event_id, type ...
Find Longest Increasing Continuous Subarray
Given an integer array nums, return the length of the longest contiguous strictly increasing subarray. "Contiguous" means the elements must appear nex...
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 decodings of a digit string
You are given a non-empty digit string s consisting of characters '0'–'9' and a mapping where 1->'a', 2->'b', ..., 26->'z'. Return the number of valid...
Group anagrams and count string in grid
Part 1 — Group Anagrams: Given an array of strings, group together strings that are anagrams of one another and output both the grouped lists and the ...
Design 2D DP on a DAG
Given a directed acyclic graph G(V, E) with N nodes, M edges, a designated source s, and an integer L, design a 2D dynamic program dp[u][k] that compu...
Solve two string algorithm tasks
Answer both parts. A) Parentheses correction: Given a string s consisting only of '(' and ')', output the minimum number of parentheses you must inser...
Find first unique character
Given a lowercase/uppercase alphanumeric string s, return the index of the first character that appears exactly once; if none exists, return -1. Provi...
Simulate Uniform(0,1) from random bits
Assume you have access to a function rand_bit() that returns 0 or 1 with equal probability and independent across calls. How would you generate a rand...
Implement DelayQueue with Idempotent Task Execution
Scenario Message broker offers DelayQueue where tasks execute at future timestamps, ensuring idempotency on duplicate IDs. Question Implement a delay ...