First written test was conducted by some third party company. It consisted of 15 objective questions from C, Sorting, Data Structures, Big O, compiler and state machine. We were given 30 minutes. Cut off was 12 out of 15 questions. 77 out of 400 students made it.
Written test 2 (Coding), 60 minutes
Three problems to be solved in 60 minutes with no use of compiler. One problem on Linked List, second on heap and third on array. I coded all problems from scratch including main method. I also wrote flexible methods that could work on any kind of inputs (instead of deleting nodes from 4 to 6, it would delete nodes between ‘M’ and ‘N’ ) and handle all corner cases. The result was announced after 20 days. 30 out of 77 made it.
F2F Interview #1, 60 minutes
We were interviewed in groups of 6. Each one of us in a group was given same problem to solve. I couldn’t code the perfect solution in an hour. All I had discussed 6 different ways to solve the problem. I was afraid that I might be rejected in first round. The interview lasted for 60 minutes.
This post was residing in my draft for quite long. I finally got some time out of my busy schedule to refine it.
The first question quickly pops up on why am I writing this post at all. There are already tens of hundreds of similar compilations on web that talks about this.
Well, following reasons compelled me to do so:
Being a GFG moderator, I’ve been getting many requests from readers through various social media (FB, LinkedIn, Quora, InstaGuide) and various mail clients asking for mentorship and guidance on how to prepare for top MNCs like Microsoft, Amazon, Google etc
Having gone through similar journey and witnessing many of my friends succeeding, I feel knowledge should be shared. My experience might be useful for newer generations who happen to chase the same goal as once was mine
Please note that this article is purely a reflection of my learnings, what I followed through the years and my experience. This is NOT the only way to improvise on what is needed – your coding skills, strengthening DS & Algorithms and boosting problem solving skills. I repeat, this is NOT the only way. There are things I couldn’t follow because of time constraints or didn’t follow because I was just not aware. Please comment if I missed anything which is worth mentioning here.
Language has been a topic of debate between aspirants since years. It’s always good to master one language, knowing ins and out of it rather than hopping from one language to other. Why? Because sometimes it might happen to you that when you get a problem, you start wondering what language you should choose and your focus is compromised. When you should really concentrate on problem solving, Implementation comes later. Then while you are coding, you plan to change the language in between. This won’t serve you good in interviews. If you’re able to solve a problem in language ‘X’, eventually you will also solve it in language ‘Y’. Learning a new language is just a matter of time. A language might not be as widely used after 5 years as it is being used now. Your ability to solve a problem will what matter in the long run.
I usually switch between C and C++. If time is at its crunch, I prefer to use STL (standard library functions) instead of writing my own version of Linked List. If I want to develop a project, an android app for instance, I go for a managed language because it is easier. If I want to automate something to save my time, like replying and liking my birthday wishes, a python script is the saving grace. You got the point, right? Master one language and learn others as per requirements.
Data Structures and Algorithms
Data Structures and Algorithms is very important and serves as the backbone of problem solving.
For beginners, Fundamentals of Data Structures in C by Sahni Horowitz is good. After reading it, you should be able to understand basic Data Structures, how they are implemented and fewer examples where they can be used. Don’t expect to learn advanced DS through this. After your basic concepts are clear and you are comfortable implementing them in a language of your choice, you can work on learning algorithms and solving problems.
Many sites (including GeeksforGeeks) present problems in a very adhoc manner with no order of difficulty level. This makes things difficult for beginners because they don’t know the difficulty level of the problem they are attempting. Data Structures and Algorithms made easy by Narasimha Karumanchi is a good read after you are comfortable with the basics. It has pretty good collection of problems organized by difficulty level. Just make sure to try to solve problems on your own instead of rushing for the solution. Once you have a fair understanding of DS and have got some confidence in solving problems, jump to online portals and start solving problems from topic of your choice. GeeksforGeeks is good to start with.
Sometimes, basic DS don’t serve the purpose to solve problems and you need to know advanced DS. Day to day problems like implementing a prefix based search for a phone contact list to finding the dictionary word from a jumbled sequence of characters need special kind of DS. There are many of them – TST, Trie, Suffix tree, Suffix array, Fibonacci heap, Segment tree, Gap buffer, Rope, Skip list, K Dimensional tree and so on. While it is good to know the implementation of these DS, I would suggest to also know when to use one.
So you got a gun, understand how to use it, probably have used it before. If you are going to fight a war, you won’t like to rely upon your amateur experience. You would prefer to practice hard to save your ass. Now try to think it in perspective of problem solving. You know what DS are. But you also need to know when to use one. Welcome to the world of problem solving. You are given a problem and you are asked to solve it. That problem can be anything starting from a simple puzzle to implementing a user scenario. You must have noticed degree of connection feature in LinkedIn. How will you implement it? Does your approach take care of scalability? Will your code crumble when user base increases ten folds? This is the most important skill top MNCs usually look for. How do you approach a problem? How do you divide it into modules? How do you solve each of them and then combine them?
I separated out DP because it is one monster which is difficult to master upon. No matter how many problems did you solve in the past, a new DP problem can always surprise you. The more you will practice, higher the chances will be to find out patterns. Google is peculiar about DP. You should expect at least one DP problem per interview round if you are preparing for Google. Practice DP section from:
Competitive Programming plays a very important role in boosting problem solving skills and ability to perform under time pressure. Do participate in various online portals like TopCoder, CodeChef, SPOJ. Here is a post on Getting started in sport of programming.
Design and testing
So you are good in DS and Algos. You are probably good in problem solving as well and you come up with different approaches with varying time and space complexity. The problem which you solve in Competitive Programming is well defined and has to work under an environment which nobody will probably use. What if you are asked to implement a user scenario. The problem statement is usually vague and you need to discuss a lot to resolve ambiguities. This is where design comes into picture. How will you design a redo-undo feature? What data structures will you use to store history in a web browser? How will you implement auto-complete feature in address bar? Let’s say Amazon wants to build a feature that would resume a video stored in cloud from any device. What data structures will you use? How will you scale up things? Does your design take care of concurrency issues? What about the performance? What if you and your girlfriend share the same cloud account and are trying to play the same video from different devices?
Now you have thought through the design well, have come up with different data structures to use with pros and cons in mind. While implementing, you must take care of corner cases. You must be aware about the integer overflow issue in Youtube video view count. While implementing, they never really thought that the view count can exceed what an integer variable can hold and BOOM, the view count cycled back to zero.
Before a feature goes live, it must be tested well. It is good to practice some test questions as well. How will you test a Insert image feature in MS Word? What about a cut-copy-paste feature? How will you test Temple Run game? Try to write all the possible test cases and how you are going to handle this in your code. Writing a robust code is very important. If you take care of these things at an earlier stage, you can avoid silly bugs (and boost your chances of getting selected in interviews).
Have a sound understanding of Operating System. The dinosaur book by Galvin is a good read. Know how networking works and have insights on DBMS.
First impression is the best. Resume is the first thing that HR will use to decide whether to call you for interview or not. And they have got hundreds of them. So they will usually scan it for 20 seconds to 2 minutes. It should be clean, concise and elegant. Each word mentioned should worth the space it eats. The rule of thumb is if you have less than one year of experience, the size of resume should not exceed a page (with few exceptions).
Few points to note:
Maintain a header to fit info like name, email id, address and contact number
Mention level of expertise corresponding to each language. Example: Proficient in C and good at Java
If you are mentioning a project, write your key learning, impact in the team and . If this project is online (an app), don’t forget to include the link. This will show that you built something that is being used by people . Guess what, this is what companies do, building a product, stabilizing it as per user feedback, taking in new feature requests and so on.
I get many messages asking me for a favour to refer them. When I ask them how much comfortable they are with DS and Algos, they say good enough. Then I rephrase my question to how do they feel when they solve interview experiences at GeeksforGeeks. Either they haven’t heard of GeeksforGeeks or they never read. This is not a surprise. GeeksforGeeks is still growing. But when I ask them a problem on DS by tweaking already existing famous ones, all they say is they haven’t solved this problem before. Please do NOT do that. Dreaming is good, but it will come true only when you work towards making it a reality.
If you are not able to clear the interviews, you will have wait again for 6-12 months depending on the company policy before you can apply again. Now coming to the point, you can apply for a position at Microsoft either through Careers page or through referral. Referral usually bumps chances of getting an interview call because your resume gets to the system through a person Microsoft trusts to be a good engineer. How do you ask for a referral? It’s simple. Forward your resume to someone you know working there. No one will say NO unless your resume is filled with something which doesn’t fit company requirements. Rule of thumb is we believe in solving problems and if you are good at it, we would love to see you here. Remember, everyone wants to work with a smart person. And this is usually true for any company, not just for Microsoft.
Do’s and Don’ts
Practice, practice and practice
Make a habit of writing clean and readable code (avoid variables names like i, j)
Make sure to handle all corner cases
Use pen and paper to practice code. In interviews you have NO access to a compiler
Don’t mug up the solutions. Try to solve on your own
Think of different ways of solving a problem and thoughts on why one should be preferred over the other
I have answered few questions related to interview preparation on Quora. You might find some content missing here in blog and it is intentional to avoid the duplication of efforts. Please read my technical answers here.
Resources (which I haven’t talked about):
Cracking the coding interview by Gayle Laakmann: A must read once before interviews. It covers aspects like what interviewers expect from you, how to deal with behavioral questions and few interesting problems. It will change your thoughts about design and test problems for good
GeeksforGeeks: A bible of problems (with well explained solutions). Make sure you do NOT rush for solutions. Try to solve problems on your own no matter how much time does it take. With time and honest practice, you should get better
CareerCup: A huge collection of problems. Though you can’t rely upon solutions, it provides a rich community for discussing problems. I found it good for discussing design problems
Project Euler: A heaven for mathematics lovers. You solve the problems using some formulas on paper and then write code to get the final solution. Solve at least 40 problems from this site.
There were countless moments of mood swing. I already had an offer from Microsoft. I wondered if I should try for other biggies like Facebook or Google. Bottom-line was, I had fallen into procrastination trap. I was shy of 9 months to join Microsoft. I wanted to enjoy life. I wanted to take a break. My then friends at Google and Facebook had mixed suggestions.
“Dude, you should really give FB a try. I can refer you and interview would be scheduled in 2 weeks”.
“It’s time to explore. Once college is over, you are never gonna get it. This is the time to have some fun”.
Out of those precious 9 months, I spent 5 months at home doing almost nothing. Major chunk of my time was invested in only eating and chatting. When boredom seemed to kill me, I just used to compile an article on GeeksforGeeks. It was fun.
Sometimes even a simple mail gives you goosebumps. I had a message from Google recruiter mentioning my profile looked interesting and if my interest was aligned, they could commence the interview process. With the mail was attached a video covering their expectations from a candidate in Google. I thought of giving a try to Google. But my practice was at a slower pace. Writing articles and solving problems were just to kill time and pure altruistic. Google is a big brand. I definitely wanted to try my luck there. It was just not the right time. It would be a pleasure to enjoy Microsoft etiquette for the time being.
July 13, 2013
The next phase begins
A long rest had finally come to an end. Nothing could make me happier than to see a person waiting at the airport holding a placard with my name imprinted on it. He directly drove us to Rejenta One. A month stay in a 5 star hotel, dedicated car, a driver, couple of good friends and new city. Whole world around me was screaming to explore it.
July 15, 2013
First day at office, mixed feelings, exhilarating and scaring at the same time. Everyone I met seemed to be pretty smart. I got Visio team, a part of Microsoft Office div. It was embarrassing that I was going to work on something I never heard of. Visio is an enterprise software not so famous among students. It captures a huge market for clients looking forward to create flow chart and diagram. In a nutshell, it is something that simplifies tens of millions of human life.
When I had a feeling that I have learnt enough to fasten my deliverable, a reorg happened and devalued most of the things that I worked upon. As they say, only skills acquired through the process matters in the long run, skills to understand and solve a problem. New team and new manager, it was a tabula rasa. Satya’s vision to focus on mobile and services landed me in an Android team. A familiar environment and some prior experience, starting was as smooth as butter. Nightmares begun when I was assigned a problem to apply effects on an image. The office codebase is huge, medieval and it’s an ocean if you don’t know where to start. I still remember those hard moments when I was just looking through the code to pick hints, searching keywords like pImage, IImage in the hope that at least the naming convention would lead me somewhere. It was one of the most fast paced project and I was (un)lucky to be a part of it. Learning was great and sleeps were compromised. My team owned low level Graphics rendering stuffs, everything that you see on screen.
Work hard, party harder
Good work should be rewarded and celebrated. Microsoft knows it. It’s not a small thing to book airbuses for 300 people to fly to Goa and stay in one of the costliest luxury Hotel Leela not to mention heavenly parties and unlimited food and drinks. This is how we celebrated our Android release and combined it with an out bound training.
As I am writing this, another reorg has landed me in Apple team. Good thing is I have got chance to take a closer look at apple products and its OS. Some of the nasty rendering bugs still give nightmares. It becomes worse when you get response on the top of your fix mentioning that your change would be impacting X millions of customers. I have learnt that this is part of life and as long as your learning curve is steep, things would just work fine.
Life at Microsoft in a nutshell
It’s been 3 years since I joined Microsoft. 3 projects, 5 managers, lots of learning, challenges, obsession to achieve the best and never ending work. The journey has been no less than a roller coaster.
Every year or so, a reorg happens and either the project or manager changes. Every time It’s a tabula rasa. As they say, change is the only constant in life. Good thing is you always get to work on something new with new people, diversity at its best.
In office team, we spend most of the time reading code, talking design stuffs and less time writing real code that goes in production. The impact is so huge that we can’t afford critical mistakes.
Effort is important, but knowing where to make an effort makes all the difference!
The type of work can be summarized by a very short story.
A giant ship engine failed. The ship’s owners tried one expert after another, but none of them could figure but how to fix the engine.
Then they brought in an old man who had been fixing ships since he was a young. He carried a large bag of tools with him, and when he arrived, he immediately went to work. He inspected the engine very carefully, top to bottom.
Two of the ship’s owners were there, watching this man, hoping he would know what to do. After looking things over, the old man reached into his bag and pulled out a small hammer. He gently tapped something. Instantly, the engine lurched into life. He carefully put his hammer away. The engine was fixed!
A week later, the owners received a bill from the old man for ten thousand dollars.
“What?!” the owners exclaimed. “He hardly did anything!”
So they wrote the old man a note saying, “Please send us an itemized bill.”
The man sent a bill that read:
Tapping with a hammer………………….. $ 2.00
Knowing where to tap…………………….. $ 9,998.00
There were many times I thought of a switch. The thing that always seemed to hold me was the thought that I would be doing the same kind of work that I am doing here. Besides, I am happy here, living life as I always wanted, trying out different things, exploring.
GeeksforGeeks after Microsoft
I usually get messages like, Why my contribution to GFG has slowed down. Is it because of my busy schedule?
Seriously speaking, the passion which was ballooned inside me 3 years ago has faded. Coding is not the only thing that fuels me. In my college days, I used to code for fun. Whenever I found myself struck by the boredom lightning, solving a new problem or brainstorming a better solution was the saving grace. My contribution has been greatly compromised and now if I write, my focus is more on the quality rather than quantity.
Sometimes I ask myself, what do I know except coding? Is my life all about staring at the screen and writing geeky characters? A lot of things are there in the world and you won’t know what you would like the best until you give it a try.
For the past few years, I had been wondering what my life is meant to be, what are the things out there which will render me with greatest pleasure, what is the secret ingredient of being happy.