🚀 The Ultimate SDE-1 Master Roadmap & Interview Question Bank

Target: SDE-1 (6 LPA - 12 LPA)
Companies: Flipkart, Zomato, Razorpay, TCS Digital, Deloitte, Startup Unicorns
Prepared For: Akash (The Project-First Developer)

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Part 1: The 8-Week Battle Plan (Roadmap)

This isn't just a list; it's a schedule. Stick to this to crack product companies.

Phase 1: The Foundation (Weeks 1-3)

Goal: Clear the "Online Assessment" (OA) - The biggest rejection filter.

Activity	Time/Day	Focus Area
DSA Grind	1.5 Hours	Arrays, Strings, HashMaps, Two Pointers (LeetCode Easy/Medium).
Aptitude	30 Mins	Quants & Logical Reasoning (Crucial for TCS/Wipro).
Outcome	Speed.	Solve Easy questions in <15 mins, Medium in <30 mins.

Phase 2: The Core Defense (Weeks 4-6)

Goal: Dominate the Technical Interview with your strengths.

Activity	Time/Day	Focus Area
System Design	1 Hour	Draw architectures for ResumePilot & Zyra AI. Know Why you used X tech.
Backend Core	45 Mins	Node.js Internals (Event Loop), SQL vs NoSQL, Indexing, Caching.
Outcome	Depth.	Be able to explain every line of code in your projects.

Phase 3: The Final Polish (Weeks 7-8)

Goal: Cracking the HR & Behavioral Rounds.

Activity	Time/Day	Focus Area
Mock Interviews	Weekend	Speak in front of a mirror. Record yourself answering "Tell me about yourself".
CS Theory	30 Mins	OS (Process/Thread), CN (TCP/HTTP), DBMS (ACID/Normalization).
Outcome	Confidence.	Fluent English delivery of your introduction and project details.

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Part 2: The 100 "Real-World" Interview Questions

This collection covers everything from "Hello World" to "System Architecture".

Section A: Project Defense (Your Superpower)

These questions are your ticket to a higher package. Answer these with "Founder Energy".

Architecture & Design

1. [Microservices] "You used Microservices for ResumePilot. Why not a Monolith? What problems did it solve?"
2. [Scalability] "If ResumePilot hits 100k active users, which component breaks first? How do you fix it?"
3. [Design Pattern] "Draw the Hexagonal Architecture. Explain how 'Ports and Adapters' decouple your business logic."
4. [Database] "Why Drizzle ORM? How does it compare to TypeORM or Prisma in terms of performance?"
5. [Message Queue] "Why RabbitMQ? Explain a scenario where a message might get lost and how you prevent it."

Advanced Backend

6. [NestJS] "Walk me through the NestJS Request Lifecycle (Middleware → Guard → Interceptor → Pipe → Controller)."
7. [Redis] "How are you using Redis? Is it for caching API responses, session storage, or rate limiting?"
8. [Security] "How do you implement Rate Limiting? Is it Distributed? How do you handle DDOS?"
9. [AI/LLM] "In Zyra AI, how do you manage the LLM Context Window? How does your RAG pipeline work?"
10. [Docker] "Explain your Dockerfile optimization. Why is COPY package.json done before COPY . .?"

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Section B: Data Structures & Algorithms (The Filter)

Don't memorize code. Memorize the Logic and Patterns.

Arrays & Strings (High Priority)

11. [Classic] Trapping Rain Water.
12. [Sliding Window] Longest Substring Without Repeating Characters.
13. [Binary Search] Search in a Rotated Sorted Array.
14. [Two Pointer] 3Sum (Find three numbers that add up to zero).
15. [Hashmap] Group Anagrams.
16. [Kadane's Algo] Maximum Subarray Sum.
17. [Intervals] Merge Intervals.

Linked Lists & Stacks

18. Reverse a Linked List (Iterative & Recursive).
19. Detect a Cycle in a Linked List (Floyd’s Cycle Finding Algo).
20. Implement a Queue using Stacks.
21. Valid Parentheses (Stack).
22. Next Greater Element.

Trees & Graphs (Product Company Favorites)

23. Level Order Traversal (BFS) of a Binary Tree.
24. Lowest Common Ancestor (LCA) in a BST.
25. Number of Islands (Grid DFS/BFS).
26. Validate Binary Search Tree (BST).
27. ZigZag Traversal of a Binary Tree.
28. Maximum Depth of a Binary Tree.

Dynamic Programming (Basic)

29. Climbing Stairs.
30. House Robber.
31. Longest Common Subsequence (LCS).
32. Coin Change Problem.

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Section C: JavaScript & Node.js (The Core)

Expect deep-dive questions here. You cannot fail this section.

33. [Event Loop] "Explain the Node.js Event Loop phases (Timers, Poll, Check) with a diagram."
34. [Async] "process.nextTick() vs setImmediate() - Which runs first?"
35. [Closure] "What is a Closure? Give a real-world example (e.g., Data Privacy)."
36. [Scope] "Explain var, let, and const in terms of Hoisting and Temporal Dead Zone."
37. [Coercion] "== vs ===. Explain with an example where == causes a bug."
38. [Async/Await] "Promise vs Async/Await. How do you handle errors in async functions?"
39. [Flow Control] "What is 'Callback Hell'? Write code to fix it using Promises."
40. [Performance] "Node.js is single-threaded. How does it handle concurrent requests? (Libuv)."
41. [Streams] "How do Streams work? (Readable, Writable, Pipe). Why use them for file uploads?"
42. [TypeScript] "Interface vs Type. When to use which?"
43. [Generics] "Write a generic Typescript function to swap two variables."

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Section D: CS Fundamentals (The Degree Check)

Service-based companies (TCS, Wipro) love these questions.

DBMS (Database Management)

44. [ACID] "Explain ACID properties with a banking transaction example."
45. [Keys] "Primary Key vs Unique Key vs Foreign Key."
46. [Normalization] "Explain 1NF, 2NF, 3NF. Why is 3NF important?"
47. [Indexing] "How does a B-Tree Index make reads faster but writes slower?"
48. [SQL vs NoSQL] "When would you choose MongoDB over PostgreSQL? Be specific."
49. [Query] "Write a SQL query to find the 2nd Highest Salary."
50. [Query] "Explain GROUP BY and HAVING clause."

OS (Operating Systems)

51. [Core] "Process vs Thread. Which one is lighter?"
52. [Deadlock] "What is a Deadlock? What are the 4 necessary conditions?"
53. [Memory] "Segmentation vs Paging."
54. [Concurrency] "Multithreading vs Multiprocessing."
55. [Kernel] "What is the Kernel in an OS?"

CN (Computer Networks)

56. [Protocol] "TCP vs UDP. Why is video streaming often UDP?"
57. [Browser] "What happens when you type google.com and hit Enter? (DNS -> IP -> Handshake)."
58. [Security] "HTTP vs HTTPS. Explain the SSL/TLS Handshake simply."
59. [Model] "Name the 7 layers of the OSI Model."
60. [Status Codes] "Meaning of 200, 301, 401, 403, 404, 500."

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Section E: System Design (SDE-1 Level)

Don't panic. Just use your common sense from your projects.

61. [Scaling] Vertical Scaling (Bigger Machine) vs Horizontal Scaling (More Machines).
62. [Load Balancer] Round Robin vs Least Connection algorithms.
63. [CAP Theorem] Consistency, Availability, Partition Tolerance.
64. [Architecture] Monolith vs Microservices vs Serverless.
65. [API Design] REST vs GraphQL. What is 'Over-fetching'?
66. [Auth] JWT vs Session-based Authentication.
67. [DB Scaling] Sharding vs Replication.

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Section F: Logic & Aptitude (For Mass Recruiters)

68. [OOPs] 4 Pillars: Encapsulation, Abstraction, Inheritance, Polymorphism.
69. [OOPs] Method Overloading vs Overriding.
70. [OOPs] Abstract Class vs Interface.
71. [C/C++] Pointer vs Reference.
72. [Puzzle] 3 Bulbs and 3 Switches puzzle.
73. [Puzzle] Measure 4 Liters using 3L and 5L buckets.
74. [Clock] Angle between hour and minute hand at 3:15.
75. [Time & Work] "A does work in 10 days, B in 15 days..."
76. [Trains] Train passing a platform problem.

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Section G: Behavioral & HR (The Culture Fit)

Answer these in simple English. No Hinglish here.

77. [Intro] "Tell me about yourself." (Your Pitch: 4 Yrs Exp + Projects + Passion).
78. [Why You?] "You are from ETCE, why Software Engineering?"
79. [Failure] "Tell me about a project that failed or a bug you couldn't fix."
80. [Conflict] "Tell me about a time you disagreed with a teammate."
81. [Strengths] "What is your biggest strength?" (Self-taught, Product Mindset).
82. [Weakness] "What is your biggest weakness?" (Public Speaking - improving it).
83. [Vision] "Where do you see yourself in 5 years?"
84. [Company] "Why do you want to join Flipkart/Zomato?"
85. [Pressure] "How do you handle tight deadlines?"

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Section H: Rapid Fire (One-Liners)

Instant answers required.

86. CORS: Cross-Origin Resource Sharing.
87. Race Condition: Two processes accessing shared data simultaneously.
88. Dependency Injection: Providing dependencies from outside (Inversion of Control).
89. PUT vs PATCH: Replace whole object vs Update partial object.
90. Foreign Key: Link between two tables.
91. Null vs Undefined: Assignment vs Declared but not assigned.
92. API Gateway: Entry point for microservices (Routing, Auth).
93. CI/CD: Continuous Integration / Continuous Deployment.
94. Git Merge vs Rebase: Combine history vs Clean linear history.
95. Linux top: Shows running processes.
96. Linux chmod: Change file permissions.
97. Memory Leak: Memory not released after use.
98. SQL Injection: Malicious SQL code insertion (Use parameterized queries).
99. Idempotency: Making multiple identical requests has the same effect as one.
100. The Final Question: "Do you have any questions for us?" (Always ask about their Tech Stack).

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Reality Check for Akash

• English: Keep it simple. Don't use big words. Just be clear. "I built X using Y because Z."
• Confidence: You have built things that 4th-year B.Tech students dream of. Own that experience.
• Goal: Don't just aim for 6 LPA. Your profile is good enough to negotiate for 8-10 LPA if you clear the DSA rounds.

"Code is your voice. Projects are your proof."

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_{Made with ❤️ by Akash}