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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Find Earliest Train Route
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Implement Rate-Limited Wikipedia Crawler
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Convert IPv4 Ranges to CIDR Blocks
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Solve three algorithmic optimization and search problems
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Compute minimum semesters to finish courses
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Compute Piecewise Linear Interpolation
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Count Valid Infection Orders
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Design hierarchical path store with create/set/get/remove
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Minimize batches and allocate riders by time
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Implement Sliding Windows and LRU Cache
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Implement decay simulation and trailing-zero counting
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Explain a shader compiler pipeline
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Compute Minimum Parentheses Additions
Given a string s consisting only of the characters '(' and ')', compute the minimum number of parentheses that must be inserted anywhere in the string...
Explain HashMap internals and collisions
Explain HashMap internals and collisions In Java, describe the underlying data structures used by HashMap (e.g., array of buckets, linked lists vs tre...
Validate KYC CSV Records
This question evaluates skills in CSV parsing, string normalization, field-level validation, and rule-based text matching, emphasizing attention to ed...
Design Sliding-Window Average Tracker
This question evaluates design and implementation of a time-windowed tracking data structure, focusing on streaming aggregation, handling monotonic ti...
Implement string compression and decompression
This question evaluates proficiency in string manipulation, run-length encoding concepts, parsing numeric counts, and validation of encoded formats, i...
Design a Recoverable Iterator
This question evaluates data-structure and state-management skills, focusing on iterator semantics, snapshotting/restore mechanics, and efficient time...
Implement three whiteboard coding tasks
The interview report described several coding questions in the same category: 1. Binary search: Given a sorted array of integers and a target value, r...