Key takeaways
- Learn one language, core data structures and problem patterns, then practise timed and mock interviews.
- Two to three months of daily practice is typical, with 150 to 250 well-chosen problems.
- Ask before searching in live interviews; online assessments usually forbid outside help.
- Cracking the Coding Interview still builds fundamentals, and Beyond CtCI updates it for patterns.
- Use your strongest language, often Python, and practise on LeetCode, NeetCode and assessment platforms.
A coding interview tests problem solving with data structures and algorithms, usually by solving one or two problems while explaining your thinking. Preparation follows a roadmap: one language, core data structures, patterns, timed practice and mock interviews. I lead engineering at SCULT INDIA and mentor students preparing for placements, so this page covers a roadmap, prep time, whether you can Google, Cracking the Coding Interview, the best books, languages, platforms and courses, and a worked example.
What is a roadmap for coding interviews?
Pick one language, learn core data structures and their complexities, then study problem patterns, practise timed problems, add system design basics for experienced roles, and finish with mock interviews. Each stage builds on the previous one.
A practical order: arrays and strings, hashing, two pointers and sliding window, stacks and queues, linked lists, binary search, recursion and backtracking, trees and binary search trees, heaps, graphs with BFS and DFS, and dynamic programming. Learn the pattern behind each problem rather than memorising solutions. Track mistakes in a notebook and revisit them. For behavioural rounds, prepare stories about projects, conflicts and failures, since many interviews combine coding with conversation.
How long does it take to prepare for a coding interview?
Community advice usually says two to three months of consistent practice for someone who knows a language, and four to six months starting from weak fundamentals. Consistency matters more than total hours.
Also asked as: how long to prepare for coding interview reddit
A common plan is one to two hours daily: learn a topic, solve three to five problems on it, and review mistakes. Many candidates feel ready after solving 150 to 250 well-chosen problems across patterns, not thousands of random ones. Add mock interviews in the final weeks, since explaining aloud under time pressure is a separate skill. If interviews are close, prioritise the most common patterns: arrays, hashing, two pointers, trees, graphs and basic dynamic programming.
Can you Google during a coding interview?
It depends on the company and format. In live interviews, ask the interviewer first; many allow looking up syntax or standard library details, but not solutions. Searching without permission can be seen as cheating.
Also asked as: can you google during coding interview reddit
Online assessments usually forbid external help and may monitor tabs or webcams, so read the rules. Take-home assignments often allow documentation and searching, and sometimes AI tools, but you must understand everything you submit. If you forget a method name live, say so and describe what it does; interviewers care more about problem solving than memorised syntax. Using AI assistants during interviews is generally prohibited unless explicitly allowed, and detection is increasingly common.
Is Cracking the Coding Interview still relevant?
Yes, for fundamentals. Its explanations of data structures, Big O, problem-solving approaches and interview behaviour remain useful, though its problem set is older and less aligned with today's pattern-based practice on platforms like LeetCode.
Many candidates use it to build foundations, then practise curated problem lists online. In 2025, Gayle Laakmann McDowell and co-authors published Beyond Cracking the Coding Interview, which updates the approach with pattern-focused guidance and modern interview advice. Treat any book as a guide to thinking, not a list to memorise. Combine reading with timed practice and mock interviews, since recognising patterns quickly under pressure is what interviews actually test.
How many pages is Cracking the Coding Interview?
The sixth edition of Cracking the Coding Interview runs to roughly 700 pages, including 189 programming questions with solutions, plus chapters on the interview process, behavioural questions and core computer science topics.
You do not need to read it cover to cover. A practical plan: read the chapters on Big O, problem-solving techniques and behavioural interviews first, then work through the data structure chapters that match your weak areas, solving problems before reading solutions. Spend more time practising than reading. If time is short, combine selected chapters with a curated online problem list, which covers the most frequently asked patterns efficiently.
What is the best coding interview book?
Popular choices include Cracking the Coding Interview for overall preparation, Beyond Cracking the Coding Interview for a modern pattern-based approach, Elements of Programming Interviews for harder problems, and Grokking Algorithms for a gentle visual introduction.
Also asked as: best coding interview languages
For system design rounds, System Design Interview by Alex Xu is widely used, and Designing Data-Intensive Applications builds deeper understanding. Choose one main coding book and one practice platform rather than collecting resources. Books explain why approaches work; platforms provide repetition. Read actively: attempt each problem first, time yourself, and write the solution in your interview language. Revisit problems you missed after a week to confirm you learned the pattern.
What is the best language for coding interviews?
Use the language you know best. Python is popular because its syntax is concise and its standard library is rich, which saves time. Java and C++ are also common, especially where interviewers expect explicit types or performance awareness.
Python lets you write solutions faster, with built-in lists, dictionaries, sets, heaps and sorting. C++ offers the STL and is favoured by competitive programmers. Java is widely used in enterprise interviews. JavaScript is fine for frontend roles. Whatever you pick, know its standard data structures, the complexity of common operations and its pitfalls, such as integer overflow in Java and C++ or mutable default arguments in Python. Switching languages late in preparation usually costs more than it gains.
What are the best coding interview platforms?
LeetCode is the most widely used for interview-style problems, with company-tagged questions and contests. NeetCode organises problems into patterns with video explanations, and HackerRank, CodeSignal and HackerEarth host many companies' online assessments.
For mock interviews, peer mock interview platforms and services like interviewing.io let you practise live with others. Codeforces and CodeChef build speed and depth through competitive programming. A balanced setup: one curated list, such as NeetCode 150, on LeetCode for patterns; one practice assessment on HackerRank to learn the format; and weekly mock interviews in the final month. Track solved problems by pattern, not just count, to find weak areas.
What is the best coding interview prep course?
Good options include NeetCode's courses and roadmap, Grokking the Coding Interview patterns, free university algorithms courses, and structured problem lists. The best preparation combines a pattern-based guide, daily practice and mock interviews.
Free resources are sufficient for most candidates: NeetCode's free videos, the Tech Interview Handbook, MIT and Princeton algorithms lectures, and LeetCode's explore cards. Paid courses help mainly with structure and motivation. Whatever you choose, measure progress by timed performance on unseen problems. Students preparing for placements should also practise aptitude tests and core computer science subjects, such as operating systems, DBMS and networking, which many campus interviews include. Join a study group to stay consistent.
What does a coding interview example look like?
A classic example is Two Sum: given an array of numbers and a target, return the indices of two numbers that add up to the target. The interviewer watches how you clarify, design, code and test, not just the final answer.
A strong walkthrough: clarify inputs, such as whether duplicates exist; state a brute-force approach checking all pairs in quadratic time; improve it with a hash map storing each number's index, giving linear time; code it cleanly; then test with examples, including edge cases like negative numbers or no solution. Explain complexity at the end. This structure, clarify, plan, code, test and analyse, works for almost every coding interview problem.
Sources
GenAI engineer and AI product builder with 2+ years shipping production-grade AI systems: RAG pipelines, fine-tuned LLMs, hybrid retrieval and multi-modal apps across vision, speech and OCR, architected end to end from ingestion to deployment. Leads engineering for SCULT INDIA's 14-member team, founded the 500+ member TechVerse Enclave community and has mentored 200+ students. Three hackathon first prizes: Changethon 2025 (IIT Roorkee), Product Genesis at Vividhotsava 2025 (CSJMU) and BYTEBATTLE (MeetKats).
Open to GenAI roles, hackathon judging, mentorship sessions and guest talks at colleges. For campus sessions the inviting institution covers the visit end to end: travel (a First AC train ticket for journeys up to five hours, a flight for anything longer), accommodation, meals, and pickup and drop; the honorarium and workshop fees are negotiable on WhatsApp or on the call, and requests are welcome from institutions that can cover the visit this way. Email pranjulrathour41@gmail.com.
