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.

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"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."
Schedule Non-Overlapping Meetings Efficiently
Implement a meeting scheduler that stores meetings as half-open intervals [start, end), where start and end are integer timestamps and start < end. Th...
Implement timestamped task management system APIs
You are implementing an in-memory Task Management System. All API methods are called with a timestamp representing the logical time when the operation...
Write SQL using joins and window functions
SQL Coding: Rank within Groups with Joins You are given two tables: accounts - account_id (string) - customer_id (string) - segment (string) — e.g., "...
Implement Top-p (Nucleus) Sampling in NumPy
Implement top-p (nucleus) sampling for next-token selection in a language model, using only NumPy. Given a vector of raw logits over a vocabulary, top...
Count Target-Sum Paths in an N-ary Tree
You are given the root of an N-ary tree. Each node contains an integer value and a list of zero or more child nodes. You are also given an integer tar...
Solve meeting scheduling and robot cleaning tasks
You are given two independent coding problems. --- Problem 1: Prioritized Meeting Scheduling You are asked to schedule meetings in a single meeting ro...
Implement 2048 tilt move
Problem: Implement a 2048 “tilt” (move) operation You are given a 4×4 board for the game 2048. Each cell contains either 0 (empty) or a power of two (...
Solve these algorithmic problems
You are given the following independent coding tasks. For each task, design an algorithm and implement a function that returns the requested output. -...
Solve linked list, grid BFS, and median queries
You are given three separate algorithmic tasks. 1) Reorder a linked list by odd/even positions Given the head of a singly linked list, reorder the nod...
Propagate runtime ID across API requests
Debug chained API requests by propagating a runtime ID You are given a sequence of 5 API requests that must be executed in order. - Request 1 (a POST)...
Minimize a String Using Allowed Swaps
You are given a string s of lowercase English letters and an array pairs, where each element pairs[i] = [a, b] means you may swap the characters at in...
Compute the Final Robot Score
You are given an array scores, where scores[i] is the score of the i-th robot. Robots repeatedly compete using the following rules: 1. Select the two ...
Evaluate IP Access Rules
You are given a list of IPv4 access-control rules. Each rule consists of: - an action: allow or deny - a CIDR block such as 192.168.0.0/16 You are als...
Implement Dependency-Aware To-Do List
Implement an in-memory to-do list in Python for managing tasks and task dependencies. You are given three core types to design: - TaskStatus: an enum ...
Implement discounted card purchases
Implement purchase logic for a gem-based card game. There are five gem colors: BLUE, WHITE, GREEN, RED, and YELLOW. Each Card has: - a color represent...
Implement Grid Spread and Transactional Store
You have two coding tasks. Task A: Compute Contamination Spread Time Given an m x n grid: - 0 means an empty cell. - 1 means a fresh item. - 2 means a...
Reverse even numbers in a list
Given an integer array nums, remove all odd numbers and return the remaining even numbers in reverse order (preserving no other ordering constraints)....
Implement course scheduling and rate limiter analysis
You are given two independent coding problems. --- Problem 1: Course Scheduling You are planning to take a set of courses and are given prerequisite r...
Implement a multi-rover Mars controller
Problem Build a small command-line “Mars Rover Controller” program. Single rover (v1) A rover starts at coordinate (0, 0) on an infinite 2D grid and i...
Minimum Sum of Weekly Maximum Costs
Minimum Sum of Weekly Maximum Costs You are scheduling a marketing campaign rollout. You are given an integer array costs, where costs[i] is the cost ...