INTERVIEW & OA PREP

Clear the OA, then the interview

Free, focused prep for Computer Science, Data Science & ML roles — the topics that actually come up in online assessments and interviews. Each page gives you the key concepts, the questions that get asked, and three quick checks. Jump to whatever you're prepping.

7 tracks 12 topics Common questions + checks

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How to use this

Prepping an OA this week? Start with Aptitude & OA Patterns and the DSA topics.
Data or ML role? Focus on SQL for Data Roles and Machine Learning Fundamentals.
Interview in a few days? Skim CS Fundamentals and rehearse the Behavioral round.
Every topic lists the questions that actually get asked — practice answering them out loud.

DSA

Arrays & Strings

The most common OA and first-round topic — most warm-up problems are array or string manipulation. Master in-place traversal, prefix sums, and sliding windows …

DSA

Hashing & Two Pointers

Hash maps turn many O(n²) scans into O(n), and two pointers exploit sorted or paired structure. Together they solve a huge fraction of medium …

DSA

Linked Lists, Stacks & Queues

Pointer-manipulation problems separate people who memorise from people who understand references. Stacks and queues underpin traversal, parsing, and scheduling questions that show up in …

DSA

Trees & Graphs

Trees and graphs are where medium/hard interviews live. DFS and BFS are the two hammers; most problems are a variation of traversal plus some …

DSA

Recursion & Dynamic Programming

DP is the topic students fear most and interviewers love most. Every DP is just recursion with memoization — define the state, the recurrence, …

DSA

Time & Space Complexity

You will be asked 'what's the complexity?' after nearly every problem. Fluency with Big-O — and with the trade-off between time and space — …

CS Fundamentals

OOP, OS, DBMS & Networks Basics

Core CS theory rounds are near-universal in Indian tech hiring. You don't need research depth — you need crisp, confident one-paragraph explanations of the …

Data & SQL

SQL for Data Roles

For data analyst, data science, and many backend roles, a live SQL round is standard. Joins, aggregation, and window functions cover the vast majority …

ML & Data Science

Machine Learning Fundamentals

ML and data-science interviews test whether you understand the concepts, not whether you memorised library calls. Bias-variance, overfitting, evaluation metrics, and how common models …

System Design

System Design Basics

Even for internships and new grads, a light system-design or HLD discussion is increasingly common. You're not expected to design Google — you're expected …

Aptitude & OA

Aptitude & OA Patterns

Many companies gate interviews behind an online assessment mixing aptitude, logical reasoning, and 1-2 coding problems under time pressure. Speed and pattern-recognition — not …

Behavioral

Behavioral & HR Round

The final round is often about fit and communication. Structured stories about your projects and teamwork, plus honest, specific answers, matter more than rehearsed …

Land the role you're prepping for

Prep is only half of it — you still need the interview. Browse live CS, Data Science & ML internships and check your resume match before you apply.

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