Not long back, popularity of Yahoo Messenger was at its peak. Google mail was in diapers, to be subscribed only through invitation. A time when TheFaceBook was to see light of the day and WhatsApp was never heard. Late in night, when I have nothing much to do, often I contemplate on the Tech advancement I have witnessed ever since I knew what software was. Please don’t take off your seat just yet, I am not gonna take you back to medieval age when computers sat only on the desks of rich people.
It was 2006 when I got my first PC. 256 MB DDR1 RAM, 20 GB HDD, single core processor. It’s fascinating to see users and how they use devices & services have come a long way. SaaS (Software as aService) is on the top of mind. The world is going paperless and companies which are scared of moving to cloud may fray. With overwhelming 24 billions devices connected to internet today, the emphasis on Scalability has become more than it ever was. The amount of data we produce is enthralling and mind-boggling – that’s 2.5 quintillion bytes of data per day. 90% of all the data till date was generated over the last two years. It is everywhere – AI, Machine Learning, self driving cars, home automation system. It’s the future.
Consumers, today, don’t care which Operating System they use, which device they hold in their hands and how much power those devices are packed with. They just want Software and services to work like a charm.
Every company, if they are to take the world with the storm (read Google Search, WhatsApp or MS Office) they are building, has to tackle two things eventually – Scalability and Cross Platform strategy. I would scope this blog to Scalability and leave the latter for some other day.
So what’s Scalability?
You are the founder of a finance company, often dealing with clients (read it people). Clients come to you for your hassle free, time bounded services. They are happy because you promise them to get the work done in 3 working days. That’s how you make money. For one year, you are pretty much happy. Happy clients, happy you. No big deal. More people hear about your services through word of mouth. And soon enough, you are flooded with clients from all over the world. You compromise sleeps and start working overtime. This works well for another five months before you realize that you can’t work alone. You hire more people, as beefy and efficient as you. Because businesses run on trust. You can’t just say that you don’t have time. People stop coming when you no longer provide what you promise. Scalability is when you can serve the requests in the reasonable time window by hiring more resources. Bigger hard drives, more RAM, powerful processor (more cores). That’s vertical scaling. But there is a limit on how much resources you can add to a machine. Costs go up and there comes a point when buying a new machine is cheaper and more feasible. That’s horizontal scaling.
In the next part, I would touch upon Databases, Caching, Message Queue, Sharding and few other topics before delving into System Design problem space. Stay tuned!
Vampires, we’re. Bright screens are our sun. In broad daylight, we love to stare at the geeky characters under shiny roofs. Caffeine is our rescue in times of exhaustion.
Before I begin with my journey at Microsoft, let me tell you that the views and opinions expressed are completely mine. Please bear with me as I speak, for my style is pretty inconsistent. Drowned in the pool of experiences, I am reinventing myself while writing all this. This post is bit long even for me. After all, squeezing 5 years of experience is difficult to fit in one blog. Go and grab a cup of coffee. I will wait.
Where do I start? Sticking to one place is no joke and I don’t expect anyone to stay this long, unless they are really happy. My chase for money faded away long ago and work contentment, for me, has been the driving force ever since holding the utmost importance in this agile Tech world.
When you reach the stage where you can afford all the food you want, all the travel, the cars and the entertainment, you want, what else is remaining? It becomes a never ending battle to reach to the top. A rat race, I would say. A wise man once said, “Save nothing but experiences”. If not, you would end up having all the materialistic pleasures, but your life would be wrapped up in emptiness. It would lack the sense of fulfilment you seek. While slogging away in the name of money, a day will come when you’re gonna ask yourself, “Was this all worth it?”
It doesn’t seem long back when I set foot in the Microsoft campus. But when I look back over the years I spent here, I oftentimes, get overwhelmed. Microsoft, as a company, what has always seemed to me is a great place to work at, while leaving my imprints across the globe as billions of users get to use its products.
My fascination for Microsoft products goes back to as early as 2002. In those Windows 98 days, we used to have sixty minutes of computer class once a week with one PC being shared between a class of ten students. I used to wait passionately for just 5 minutes of my hands on the PC.
May 2009 – When it all started
Memories of the tough time and the difficult decision while joining Graduation college are as fresh as morning dew. 2008 recession had plagued the software industry and associated opportunities adversely. The sheer fear of decreasing market demand of software engineers had panicked young blood to not pursue engineering in Computer Science. Despite the risk involved in those times and an admission in not so famous university, my passion & optimistic mind entwined their wings and somehow worked together, and here I am, penning half decade of my experience at Microsoft, in astonishment and all flabbergasted.
July 15, 2013
Fresh blood joins. All the vampires rejoice.
5 years it’s been and it feels like it were only yesterday when I wandered the corridors of the humongous campus for the first time. Days bled off into years. I have seen people come. I have seen people leave. Life moves on. Everyone is replaceable. The higher, one is at the management hierarchy, lesser is the tolerance for mistakes.
The time I joined Microsoft, peers around me were celebrating 5 years of completion and I had one naive question. How come they never thought of a switch? Spending long time at one place is quite a thing and more than the place, it tells a lot about the person – Happiness, Patience and sometimes they just let life go with the flow. Well, for me, it never really occurred to me that there is a world outside Microsoft that also builds awesome products and has huge user base. Having worked on world class products like Microsoft Excel and its underlying complex architecture, I feel my existence in this universe is making a mark upon people changing their lives through technology.
In this short span of time, I got to work on 6 version-1 projects each having different complexity and its own problem space. The journey has culminated in a great experience, adding a check to my learning curve at every stage.
The world of flow-charts and diagrams – Office Visio
My career started as SDET in Visio team, a part of Microsoft Office division. 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 charts and diagrams. In a nutshell, it is something that simplifies tens of millions of human life. As a test engineer, I designed test suites and wrote automation for various features to make sure the regressions are caught early and help stabilise the product.
K2 phase: It’s Android baby
When I had a feeling that I have learnt enough that would help 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 Android team. 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 fastest 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.
It was an exhilarating roller coaster ride as I had never worked on a project of that urgency before. K2 is the second most dangerous mountain to climb and so was this project. Satya’s leadership and his vision for the company was as clear as a bell. We didn’t want to box ourselves in the Windows world. This was a big leap from our past rusted thinking and it was the beginning of reinventing the company. In Satya’s words, we needed to Hit Refresh. Even if we lost the war in Mobile Operating System, Microsoft could make a mark by releasing products on other platforms. SaaS (Software as a Service) was on the top of mind and Microsoft wasn’t behind. But to truly unlock its potential, we needed to annihilate the platform barrier. The world was transitioning at steep pace and the way users used the computing devices was reshaping. Desktop PCs and laptops were no more in trend and to succeed as a company, users needed to feel connected wherever they go. What is the benefit of all those technologies when users can’t edit a document on mobile while going to office and resume on laptop? Delaying this project could have been catastrophic. Decisions are good as long as they are taken at right time.
The idea of Shared code had always fascinated me and I got a chance to see how it works. The biggest challenge of developing apps on Android was device fragmentation. Apps you build might work like a charm on one device, while it might be completely screwed up on others. This project literally boosted my confidence as I was really quick when it came to building something on Android. It was an honor to be recognized as Subject Matter Expert. When I got empty hours, I contributed to Android community on StackOverflow and earned many medals. As of now, I hold 12 gold, 48 silver and 89 bronze medals.
Apple, A costly affair
Satya’s vision for efficient engineering annihilated the concept of tester & developer and rendered everyone a Software Engineer. I moved to Graphics team for iOS where I made core design changes and wrote code to be shared across various apps cross platform. The biggest challenge was to think of design that could sail well across multiple platforms and apps. Making changes at such a lower level was risky, heart throbbing and required solid understanding. Tolerance for mistakes was minuscule and the impact was so huge that making even a small mistake had big ripple effects breaking many features across the apps. Some of the nasty bugs gave me nightmares. It becomes worse when you have to fix the bug overnight and when you do it, you get response on the top of your fix mentioning that your change would be impacting twenty millions customers. Even 1 millisecond of performance regression raised eyebrows asking critical questions related to the design and the solution. I have learnt that this is part of life and as long as the learning curve is steep, things would just work fine. It has taught me the skill to never give up. Perseverance and grit are great virtues to survive in this industry.
Before the release of K2, shared code was a myth. As much fantastic as it may sound when discussed, it was practically not possible given the platform differences, language barrier at different end points and the engineering cost involved to bring the complex humongous codebase together. With the release of WXP on Android, we proved it to be doable and sealed it after moving iOS codebase to the same shared codebase.
Having got familiarized with both Android and iOS, I must say that I would choose Android over iOS any time of the day both as a developer and a user. Apple’s developer tool XCode hangs and crashes every now and then and sucks. Things that can be achieved in a straight forward way in Android can be pain when it comes to iOS.
Recalc or Die – Excel
About 30 years ago in a place far, far away, when C++ was still in diapers, Microsoft Excel was born. We even shipped Excel on floppy. We didn’t have much of C++ that time. So we wrote our own wrappers.
Shared rendering was over and I moved to Excel iOS team where I worked on Excel rendering component. Excel is one of the most complex projects and there are dozens of layers of architecture. Few of the bugs literally drove me crazy. I remember frying neurons of my brain for days without a clue on where in the code the problem might be. Some bugs were in the Apple library itself.
Excel on Mac
Another year, another project. Some familiarity with how Excel works, at least a part of it, landed me into another Excel endpoint. This time, it was Mac. It was way more complex than iOS. The quality was super important, for most of the people with big names use Mac, all of them being paid customers. A simple screw up could motivate one of the journalists to write and given how powerful social media are these days, it could have gone viral in no time. We did get good detailed feedback from a NASA scientist which reemphasized the impact we had been making.
While working on Excel and rendering technologies was fascinating because of the huge mass reach, lack of opportunities to add much design and code in Excel troubled me. The Data Structures and design used were fascinating. But they were written in 90s. Another good thing was that I never had to explain Excel to anyone. I remember meeting a college friend in Seattle who was widely surprised when I mentioned that we are fixing bugs in Excel. She always thought Excel to be super stable.
My restless mind, always looking forward to swim out of comfort zone to try and learn new things, found its medicine when a new SharePoint team in IDC was formed. I never realised the sheer potential of SharePoint until I started working on it. New technologies & tools, two decades old product, unknown territory, ownership of core components and never ending challenges, I couldn’t have asked for more.
Normal days at Microsoft
If you wonder how normal days as a Software Engineer at Microsoft look like, well it can be summarized something like:
You get a feature and are asked to come up with a design and various approaches to develop this.
You discuss various pros and cons and why one approach should be preferred over others.
You write code to develop the functionality. If the code is not shared, Bingo! your life just got easier. If it is shared across apps and platforms , you have to make sure it doesn’t regress anything. There are tons of test cases your code must pass.
If you get a bug due to your code and it is hi-pri, a hot mail thread starts overnight stating it impacted ‘X’ millions of customers.
If you get a bug not related to your code, well happy debugging. There are tens of millions of lines of code and you don’t have slightest of clue in what layer of architecture, the issue might be. I remember debugging a bug for 8 continuous days and at the end, I found that it was a race condition issue. The bug reproduced every once in 30-40 attempts.
Your code performance is super critical. I remember being part of a burning mail thread once because my code regressed the performance by 1 millisecond. I couldn’t see the difference manually as 1 millisecond is something your eyes can’t perceive.
You think you’re smart. Well think again. There are smarter people talking to whom is so much fun. You are stuck debugging an issue for 2 days. You don’t see anything working. You are pissed off. You send a mail to the people asking for help. They read your issue on phone, respond with a fix and it works.
In a nutshell, the emphasis is more on reading and understanding code than writing a new one. If you can’t understand well what is written, how are you going to modify it? This varies from team to team. Since office was released in medieval time when C++ was still in diapers, making changes in the code becomes a bit difficult, especially when you are making changes to an existing feature.
Microsoft is full of smart people. You can learn something from almost everyone.
Why I chose to stay at Microsoft?
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 the world around me and pursuing my hobbies one after the other.
While we’re busy in earning money, life is busy in deducting time
If you ask me if I’m happy with the salary I get here. I would probably say, Yes. And I will shortly explain why. Pay is decent, but it is lesser than what competitive companies offer. Many of my friends have switched to other companies for higher pay. There was hardly a day in my 60 months of career at Microsoft that forced me to think of a switch, because of following reasons:
The best thing I like about Microsoft is the work-life balance. The timings are flexible. If you get a good manager who knows how to handle pressure well, you won’t have to work overnight unless it’s absolutely necessary.
Company culture and vision
At Microsoft, we strive to build products that amaze customers within thirty seconds of usage. If we fail to wow them, we lose them for life. That’s the underlying principle behind every Office product. Productivity and efficiency are taken very seriously. Effort is important, but knowing where to make an effort makes all the difference.
I chose to stay at Microsoft because while working here, I can pursue my hobbies. You get plenty of time for things you want to do. I travel, do fashion and landscape photoshoot, play piano and write blogs, all while writing code in week days.
Money is a good servant but a bad master
The money I earn here is enough to survive and buy things of interest. If I would earn more money, I would buy bigger car or dine in more luxurious restaurants. The standard of living will improve. But the question is, how far are you willing to go for the sake of money. Run for money never ends. Having lived my fair share of life, I realized that life should be made up of moments. As long as you are happy with what you have, you are living a good life. With more money, comes more responsibility. Yes, there are times when I regret not being able to afford a Grand Piano, but I can settle with a smaller version of it.
Although Microsoft pays lesser than few startups, I love it. My granddad proudly says that his grandson works at Microsoft. Microsoft is one of few companies that has survived four decades while staying relevant. People are still crazy about it.
Products that I work on are used by billions of people. I can say that the part of picture manipulation code in Word/Excel/PowerPoint has been written by me. This kind of huge impact can only be felt by working at some of the biggies like Google and Facebook.
When Satya Nadella took over, the change was visible sooner than we had anticipated. The company was at the cusp of transformation and is going through a significant transition phase as we speak. It’s not just a Windows company anymore. The focus has gradually shifted to its mobile first, cloud first business. The reason is simple. With so many technological advancements and automated home & car systems generating a lot of data, the humongous data has to be stored somewhere. 90% of the world’s data has been generated over last two years. Microsoft is pushing hard to make a dent through providing cloud services and thereby, stay relevant.
Microsoft is in right hands. Its stocks are soaring all time high. Investors have confidence and they’re betting in its bright future. It’s far from pinnacle of success and there is a long way to go. But I believe in the company’s vision. And as an employee, it’s a great feeling and amazing place to be at, while being part of the major transformation. I can either watch it happen or be a part of it. Well, the former doesn’t excite me enough.
You might like my other posts along the same line:
If you like to read about dreams and goals, you might like my journey. I won’t claim it to be inspiring and motivating. Neither would I claim it to be struggling and unique. I will leave it for you to decide. But everyone has a journey and a story to tell. And this my friend, is my journey.
Each year when I wake up in the morning and find Facebook reminding me of this very date, I can’t stop myself to feel happy and grateful. I thank god who has graced my life with all the opportunities & happiness and given me an ability to be good at what I do.
4 years it’s been since I joined Microsoft and it feels like it were only yesterday when I wandered the corridors of the humongous campus for the first time. Days bled off into years. I have seen people come. I have seen people leave. Life moves on. Everyone is replaceable.
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.
Every evening on the roof top of my hostel in Delhi, I used to see the shining airplanes going off into the thin air and wondered when I would get a chance to fly in one of these with my own capability. While that dream was fulfilled the moment I joined Microsoft, I started wondering to fly to United States in the best of airlines to feel how is it like to be in the most powerful country in the world..You can say that my dreams always get upgraded.
Being at Microsoft has its own benefits
I owned an important piece of project in Microsoft. There was a talk going on to fasten the velocity of work we were doing. Given the complexity of the project, its architecture was written in many layers few of which was coded by team at Redmond. Due to time zone difference and the critical timing, we had to act on it quickly to enhance quality of product. They decided to send me over to interact with people, understand different layers and their communication.
A sudden plan
I hardly remember traveling somewhere in such a big rush. It was 4 O’ clock in the evening when I was checking flight tickets and changing date in the calendar on the online portal to finalize which day to travel. 6 O’ clock, my friends found a flight that was to take off the next morning to Seattle and I spent next hour mentally preparing myself to fly so unprepared. It was just hard to believe that I would be traveling to US, one of my dream destinations without any preparation. My parents were asking me every other day if I bought winter apparels. I usually prefer to plan everything in advance and this time, without have a flight ticket in hand, I didn’t want. With support from my friends at Microsoft, I finally decided to give it a chance. There are few things in world for which you need not to be prepared. After all, traveling somewhere without much thinking has its own share of fun. And this was not somewhere. This was what I dreamed of long enough.
It all started with a joke. I was worried I was not getting any ticket in good airlines next week. I was tired, exhausted not a clue on what to do. “There is a flight next day at 4 in the morning. You can catch that.”
“Holy cow! This would be too early. How on earth would I be able to catch that?”
I knew they were serious when my manager said. “Actually, I think you can go.”
“But I haven’t done any shopping”, my forehead was shining with worry lines.
“It’s alright. What are the things you need? You can borrow them from me.”
My friends helped to prepare an itinerary. I literally got only 2 hours to dine and pack my bags. I usually never take more than 30 minutes to pack, but since this was my first trip to US, I didn’t want to take any chances.
It’s Emirates, baby
The moment I stepped into the flight, I got the answer why it has been coined as the best airlines in the world. The service, the infra and the experience was just amazing. It is very unlikely that you would be left unhappy after an Emirates travel. It was a 22 hours long journey with a 3 hours layover in Dubai. Being a movie buff and their huge collection of movies, I didn’t find it difficult to spend time.
Hello from Redmond!
The flight was just on time. You might find it funny but the first thing I missed at Seattle airport was no taxi driver asking me where would I want to go. I didn’t have US Sim Card and it was freezing cold to stay for long in the open weather. There are two Marriott hotels in Redmond and I missed to mention which one I wanted to go to the local taxi. Even with a 50% chance of landing at the correct hotel didn’t work for me. Redmond is kinda a developed village. It’s hard to find anyone on the road. It was near difficult to ask someone for navigation. Luckily, the second Marriott was just a few blocks away.
Few of the pictures of the hotel:
I learned that labor is costly in US. The gorgeous lady at the business center handed me over a map which had directions to follow my room. It’s very unlike in India that you would have to carry luggage to your room on your own in a decent hotel.
My first status update from Facebook on the arrival night.
It’s been only 11:00 PM here and I am done with sleep. It’s quite chilly outside and the roads are empty. A grave silence is there in the winds. Next couple of nights, I am gonna spend as a night crawler. I wonder if the new government would encourage vigilante. All of a sudden, I feel like I have all the time in the world and I have very less to do.
If I was not able to respond to your chats due to my busy schedule, Let’s catch up now
Being a hobby photographer, I found everything very interesting and screaming at me to be clicked.
The view outside my hotel room. As you can see, cars are parked in the open air. In the morning, the car windows are covered with a thick layer of ice.
Just by the first look, I can say that discipline and patience flow in veins here. I never saw anyone rushing, everyone (well almost) greets you with a wide smile, cute children laughing on pavements and the most important thing – punctuality. People prefer to be on time. They dine by 8, sleep by 11 and woke up at 6.
Good morning Redmond
It is said that breakfast is the most important meal of the day. You don’t realize it until you skip dinner and have a heavy breakfast in Indian style dinner.Good morning Redmond!
I was under impression that I won’t be getting sleep at usual time because of all the jet lag stories I heard. To my surprise, jet lag did magic to my schedule which I couldn’t follow even after trying for 10 years and many apps claiming to help you do so. I slept at 10, wake up at 6 and rushed to office by 8. It was just an amazing feeling. It was refreshing. I was way more productive. I never knew a good schedule can do miracles in your day to day life.
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. It’s one thing to yearn for something. But quite other to put efforts to make 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.