Coding & Algorithms Interview Questions
Practice 3,429 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."

"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."
Minimize changes for k-periodic palindrome
Question Given a string currentPassword (length N) and an integer k (1 ≤ k < N, N ≤ 2·10^5, lowercase letters, N divisible by k), find the minimum num...
Solve binary-search knapsack & graph shortest path
Question Given a sorted list of items, design an efficient solution (using binary search) to achieve the target objective instead of a dynamic-program...
Recommend friends-of-friends
Question Given a dictionary such as {A:[B,C], B:[C,D], C:[E]}, return for a user U all people followed by U’s followees but not already followed by U....
Implement Connect Four game
Question Design and implement the Connect Four game board, player moves, and winner-detection logic. Discuss time/space complexity and possible follow...
Solve stock trading with pattern rules
Question Given an array of daily stock prices and two pattern arrays: sellPattern and buyPattern, each consisting of 1 (price up) and -1 (price down) ...
Compute statistics in data stream
Question Design a data structure that supports computing the current max, mean, and mode for an unbounded integer data stream. Estimate the memory usa...
Count partitions and equal-cost packages
Question Given a string itemCategories, count the number of ways to partition it into exactly two contiguous non-empty substrings (a prefix and a suff...
Count uniques in sparse sorted array
Question A sorted array contains many duplicates but only a very small number of distinct values. Design an algorithm that counts how many unique numb...
Maximize vacation streak with PTO
Question Given an array of characters containing 'w' (workday) and 'h' (holiday) and an integer n representing the number of PTO days you can convert ...
Handle invalid Lisp expression parsing
Question LeetCode 736. Parse Lisp Expression – Given a string representing a Lisp-like expression containing let/add/mult operations and variable bind...
Solve palindrome pairs and key path
Question LeetCode 336. Palindrome Pairs; LeetCode 864. Shortest Path to Get All Keys https://leetcode.com/problems/palindrome-pairs/description/ https...
Solve Open the Lock BFS
Question LeetCode 752. Open the Lock – Given an initial lock state "0000", a target combination, and a list of deadend combinations that cannot be use...
Delete duplicate files via DFS
Question LeetCode 609. Find Duplicate File in System – Implement an algorithm (using DFS/backtracking) to delete files with duplicate content in a fil...
Find duplicate files by size
Question LeetCode 609. Find Duplicate File in System — find duplicate files using file size instead of content comparison https://leetcode.com/problem...
Solve Rotting Oranges and Bus Walk Reachability
Question LeetCode 994. Rotting Oranges. 2) Given start and end grid coordinates, an integer k (maximum walking distance), and a bidirectional graph of...
Compute max-ons and deletion indices
Question Given a circular array of n computers represented by 0 (off) and 1 (on), determine the maximum possible number of on computers within any con...
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...
Merge overlapping intervals
Question LeetCode 56. Merge Intervals – Given a collection of intervals, merge all overlapping intervals into one and return an array of the non-overl...
Implement test failure analytics APIs
Question Design a data structure that supports: log(testId, timestamp, status) — record the status ('pass'/'fail') of a test run; timestamps are stric...
Solve Data-Structure Problems in Python Interview Round
Scenario Interview coding round focusing on simple data-structure problems in Python. Question Given an integer, rearrange its digits (considering onl...