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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Compare two programs for equivalence
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Detect duplicate files efficiently
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Compare heap and stack memory
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Design a persistent key-value store
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Check Graph Reachability For File Permissions
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Find Dictionary Matches for a Jammed String
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Find path in implicit Fibonacci tree
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Implement a simplified memcached server
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Implement run-length encoding and decoding
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Convert amounts between multiple currencies
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Implement simplified Excel with SET/GET/SUM
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Check if CIDR is fully canceled by rules
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Implement Task Dependencies and Failure
Implement a Python in-memory task manager for an AI workflow system. Each task has a unique task_id and a status. A task may depend on other tasks. If...
Solve Magic Dictionary and unknown traversal
Solve Magic Dictionary and unknown traversal LeetCode 676. Implement Magic Dictionary Determine and implement traversal/encoding that outputs nodes as...
Perform matrix Candy Crush elimination
Question Implement a function that, given an m × n integer matrix representing colored blocks (same integers = same color), performs one round of "Can...
Critique Shell Script for Credit-Card Program Tech Round
Critique Shell Script for Credit-Card Program Tech Round Scenario Tech round for a new credit-card program: candidate is shown a 5-6 line shell script...
Analyze Python Functions: Improve Readability and Efficiency
Analyze Python Functions: Improve Readability and Efficiency Scenario Zoom interview code-review segment: interviewer shares three short Python functi...
Parse API JSON and print org chart
You will solve two practical coding tasks. Task 1: Call an HTTP API and parse JSON You are given an HTTP endpoint that returns JSON describing transit...
Solve pair-counting and account-merging problems
Problem A — Count qualifying products You are given two integer arrays A and B, and an integer T. For each element a in A, count how many elements b i...