Sunday, August 24, 2008

What a great family

I received these pictures from my wife and kids when I arrived in Seattle. They are a great family and I miss them. From left to right is my niece Ashlan, my daughter Brooklyn, and my son Carter. See you soon!

Wednesday, August 13, 2008

Amazon Interview

I went through my interview with Microsoft in my previous blog entry. In this entry I plan to discuss my Amazon interview. I applied to Amazon after having visited the Silicon Valley area. I knew that I didn't want to work in that area and hoped the Seattle area would be nicer. Amazon gets tons of traffic daily and I'd been very impressed with their S3 and EC2 technologies, which I discuss here. I wanted to work at internet scale and Amazon seemed to be a prosperous and growing company.

I received an email from an Amazon recruiter not too long after submitting my resume. She described the process: two phone screens where I would have to write code over the phone and then they would fly me to Seattle. I had just come off my interviews with Google and Yahoo, so I was excited to have another opportunity ahead of me.

For my first phone screen, I was out of town, so I had to do it in my car. They mentioned I would have to write code and I shouldn't be driving. I had pulled over in a parking lot and was ready with pencil and paper when the call came. I had also turned off my car and it was about 100 degrees F outside; it was definitely uncomfortable. In this first interview, he asked me to write a binary search function for an integer array. Normally I don't describe the questions that are asked; however, in this case I don't think I'm giving away any big secrets.

I wrote a recursive binary search implementation and read it back to him over the phone. It was a bit odd to read code over the phone. I had to read out curly braces, square brackets, the whole works! When I finished reading it he asked me if line X was ok. I told him that I thought it needed a +1 to it. He said ok and then asked me why I chose a recursive implementation. I told him that I thought it would be easier to write. I tend to think recursively. He asked me what the downsides of a recursive implementation are. I told him that it requires time to push on and off the stack. I also mentioned something about stack overflow, but in hindsight that was a bit silly. The greatest stack depth you can ever have for a binary search is 32 (on a 32 bit machine). I also mentioned that a tail call optimizer would eliminate the performance penalty. I'm not sure he understood that, so I didn't pursue it. Besides, I don't know of any C++ compilers that include tail-call optimizations.

We had plenty of time left, so he asked me to rewrite it iteratively. I complied and started writing it. In the middle of writing it, I realized I screwed up the recursive version. I told him about my screw up over the phone and called myself an idiot. We both got a laugh out of that. I finished my iterative implementation, double checked it for accuracy, and read it to him over the phone. He seemed happy with that approach and I mentioned that it was easier to write than the recursive version. However, I imagine that is because I had calmed down some and the recursive version had prepped me. He asked me about some of the test cases I would run on it. I mentioned as many as I could such as element not in the array, element at each end of the array, element in the middle of the array, duplicate elements, etc... He seemed satisfied and began telling me about their team and projects. In the end he asked me if I had any questions. I only had one or two about the team and working conditions. I'm not a huge questioner, I guess.

Honestly, at that point I wasn't sure I'd be getting a call back. I had flubbed the recursive version of a binary sort for goodness sake. I mean, come on, who does that? I should have nailed that one. I was a bit disappointed. (On a side note, there is a really great article on binary search in Beautiful Code. If you don't have that book, you really should.) Since my phone screen was on a Thursday evening I had to wait until the next week to hear my results. The recruiter called and told me that they were interested in talking to me further and they would like to set up another phone screen. I was excited to be moving on to the next round!

The next interviewer also asked me a fairly basic programming question. It is one that I ask a lot in interviews and therefore quickly pounded out the optimal solution. In this case, it seemed to take him a few minutes to verify that it worked. I was a bit surprised - I figured if you asked a question you should know the optimal answer for it. It could be that he was testing me to see if I would rush to change anything, but I was confident in my answer. He seemed pleased and we moved on to talking about other things. After this interview, I was pretty confident that I would be getting to go to Seattle and after a few days, the recruiter called to confirm it.

There were a few negatives about the trip to Seattle with regards to Amazon. First, the put you in a hotel downtown, which means that you are within walking distance to everything. That's not a negative. However, they don't imagine you need a rental car, so they don't provide one. Instead, they reimburse you for taxis. Now, I appreciate being reimbursed, but it is a lot of trouble. I have to find the cash to pay the taxis, get receipts, keep the receipts, turn them in, and wait 6 weeks for the money. Honestly, it's just not worth it. Secondly, the hotel they put me in didn't have free in room internet. I wasn't going to pay $10 a day to get it, either. They did have free internet in the lobby, so I would go down there, download an Ars Digita Video Lecture and go back to the room to watch it. I will say that the staff at the hotel was very courteous and the restaurant was great, but not having in-room internet sucks. Big time.

Amazon flew me in a day before the interview, so the first day I was there I went and walked around the downtown area. I found it vibrant and clean. I went to a suggested restaurant nearby and had some really amazing food. However, it was getting late and I was tired, so I went back to my room to rest up for the next day.

The next day I awoke and took a taxi to the Amazon building. It was on 5th street South. Either that or 4th Street South. I forget. But the reason I bring it up is because the directions explicitly say that South is different from not South :) In other words, they are on different ends of the town. I'm paranoid that my taxi driver won't know that and keep repeating to him, "South, right? I mean it's a different street or something." We get on 4th Street (or 5th Street...who knows...) and it's not South and I'm repeating again "4th Street South!". Finally, he assures me that he knows where he is going and I should just let him take me there. I sit back, say "ok", and enjoy the ride. We drove by the Seattle Public Library and I am amazed by its architecture. It is truly stunning.

Finally, we arrive at our destination. He lets me out and he pulls off after giving me a blank receipt. For that matter, all the taxi drivers have given me blank receipts. Do I fill in the amount and sign them myself? I have no idea. Anyway, I'm looking around and I don't see an Amazon sign anywhere. I'm freaking out thinking "Oh my gosh, he has taken me to the wrong street!" However, I do see a street sign and it has South on it, so I must be in the right place.

Finally, I see an entryway on the side of the building with "Amazon" on it. I go inside and speak to the receptionist. I'm about 30 minutes early, so she asks me to take a seat. Interestingly enough, as I'm sitting there thumbing through magazines, I find an advertisement for my current company, Acxiom. It had to be the worst advertisement I'd seen. It was a city-scape with a lake and the words "We make information intelligent." What does that even mean? How do I know what Acxiom does from that? I sat there for about 10 minutes coming up with better advertising campaigns. It wasn't hard. Having worked at Acxiom, I am Jack's complete lack of surprise.

A little after the appointed time, my first interviewer came and got me. He didn't say much as he walked me to the room where I would spend the rest of the day. In fact, once we were in the room he immediately asked me to code the solution to a problem. There was no introduction, soft-skills questions, or questions to make you comfortable. It was just an immediate call for action. I did well on the first question, though it took the entire time. The next interviewer had to wait outside the door a bit for us to finish up. The only odd thing was that I still have no idea what the first interviewer's name was or on what team he worked.

The second interviewer was a bit better, I think he told me his name :) However, he once again avoided any comfort questions and went straight to the coding ones. He asked a question that I put to my CS 101 students. I told him that it is a programming assignment that I give them and that it is usually a bit long to write out; however, I hoped I could do a better job than they could. Still, the program just takes time to write and it took up an entire whiteboard by the time we were done. He asked quite a few questions about it and I fixed a few bugs reading back through it. He also asked me how I would test it and I went through the various scenarios. One of those scenarios failed with my current implementation, so we fixed that as well. Then, it was time for the next interviewer.

The next interviewer asked a design question. It was a question that I had some familiarity with it as it included aspects of record linkage. In fact, I explained a few things to him from the leading edge of research that he was not familiar with. We got into a little debate about whether user click-streams could be substituted for a heuristic algorithm, but on the whole it was a good interview.

After that, it was the team's boss's turn to take me out to lunch. Amazon doesn't have a cafeteria (at least they didn't take me to it), so we went across the street to a Thai restaurant. Turns out my interviewer liked the same type of food I did and we ended up ordering the exact same thing. We talked about my experience and work history over lunch and he talked about the team. He mentioned a number of times that it was a production team and I would have to carry a pager. He wanted to make sure I was ok with that. I told him that I was and that I had done support in the past and was fine with it.

When we returned to the office, it was his turn to ask questions. His were more logic/match puzzles. At first, he started by saying "You have an array..." and I thought, "Oh boy, here we go again." Pretty much every company asks the same array question. "You are given an array with N integers. Each integer is in the range of [1,N-1]. Furthermore only one integer is repeated. How can you find the repeated integer?" I got this question and variants of it in 3 of the 4 interviews. I was getting ready to answer it again for Amazon when he threw a curve ball and asked a variant of it that I had never heard. This one was more interesting and actually fun. Now, I don't think that this type of question shows anything about the programmer other than whether or not he's heard the question before. It's kind of like the moving Mt. Fuji questions of old. However, I worked through the question, got the "Aha!" moment, and solved it. I tend to like solving those questions. Even though it didn't say anything about me as a programmer, I had fun with it.

The next interviewer was to assess my C++ and OO design skills. He asked me stock C++ questions, which I answered without difficulty. He then posed a coding question that was really more about interface design than actual coding. I had to do things like make sure my constructor was correct and write operator + in terms of operator+=, etc... I wasn't familiar with the domain (and told him so), but in the end I came up with a solution. He told me that it was the same solution he came up with when he first attempted the problem. However, he had to do it in a production setting, not an interview setting. I felt like coming up with the same solution as my interviewer was a good thing, so I was ok with that.

The final technical interview of the day was another design question. It was with this question that I had the most trouble. It was a question that was directly related to how they track and update pricing information. I tried to use a database to help solve the problem. I'm not sure if this was the right approach or not as it really constricted me. In the end, I came up with a pretty pathetic solution to a very complex problem. I don't think either the interviewer or I was happy with it. It was the one interview that I sucked at :)

After that was supposed to be the boss of the second team I interviewed with. However, he was out of town so he sent a sub :) This person described his team and the other team that I was interviewing for. I asked a lot of questions trying to distinguish the teams. I don't know that I ever could distinguish between the two teams, they were so similar. The only difference I could gather is that one was also responsible for a new framework.

After not getting the team structure sorted out, I was on to the final meeting of the day. It was with the human resources person. He and I chatted about a few HR matters and then he showed me to the lobby where they called a taxi for me.

On the whole, my experience with Amazon was just "OK". They were obviously not a "tech" company. Their dress code, lack of free drinks, and general frugality said that they were a retail business. The employees were smart, but seemed a bit like "cowboys". Their plans were overly ambitious and I wondered about their success rate. I'd also read online about how hard they worked and how little they were rewarded for it. Now, I certainly don't believe everything I read online, but it can't help but color your views.

In the end, I thought that Microsoft would be the better choice. I've never worked for a "true" tech company and the search space was very exciting. I really enjoyed visiting Amazon and I'm sure it would be a fantastic company to work for, but in the end the prospect of working for Microsoft was too good to pass up.

Well, I hope you enjoyed this second installment of my interviews and be sure to look for the third (Yahoo!) and fourth (Google) installments.

Tuesday, August 12, 2008

Microsoft Interview - Live Search

After reading about Ben's interview at Microsoft, I thought I would post my own. Perhaps I'll post my interviews at Google, Yahoo, and Amazon later.

Where to begin? Let me start by saying I'm not a Microsoft fanboy. I don't have anything against them and use Windows on my home desktop and Office at work, but that's about it. I spend most of my time in Cygwin: a linux environment for Windows. In addition, I use Emacs and Eclipse. I have programmed professionally for 8 years, 7 1/2 of those years have been exclusively in a Linux or Unix environment. My primary languages have been C++, Perl and more recently Java. For a while, I ran Ubuntu on my desktop, but the kids and wife didn't like that so much :) Nevertheless, I think you can see that I am by no means a Microsoft fanboy.

I first applied for a position at Microsoft in 2003 in their Visual Studio group. I had recently completed my Ph.D. at Clemson and thought I was God's gift to programmers. I won't go into that interview at this time, since this entry is focusing on my latest interview, but I will say I bombed badly. For one thing, I ate something that disagreed with me and spent more time in the bathroom than in the interviewer's offices. Secondly, I was interviewing for both a PM role and an SDE role and so I kept having to switch modes. Thirdly, I was bull headed and wouldn't listen to any of the interviewers. I just sucked. They said I could apply again in a year, but I didn't. I figured they had a big red X on my submission folder.

Most of my professional career has been spent at Acxiom, a global interactive marketing services firm. Primarily, I study and implement ideas around matching and record linkage. Over the last two years, we've been bringing machine learning and information retrieval research to bear on the record linkage problem and it has been very exciting. I wanted to spend more time working on those large scale problems. Therefore, I submitted my resume to a few of the larger companies: Google, Yahoo, Amazon, and Microsoft. I got callbacks from the first three. Microsoft still had that big ole X on my folder.

My Google interview was first. I'll describe it in another post, but I bombed it. I didn't study and they didn't give hints. They were a great group of people, but it just wasn't my day.

Next up was the Yahoo! interview. I thought I had bombed it as well, but apparently not. I got an offer to work with the Pig team. However, by this time I also had an interview with Amazon upcoming, so I requested that they wait for my decision until after that interview. On a side note, I think the Pig team is great and I wish them all the best in the future.

Needless to say, I was very excited after receiving the Yahoo! offer. Perhaps I wasn't an idiot after all (I had begun to wonder after the Google interview - and my wife was making fun of me!). The first thing I did was announce it on twitter. The funny thing is, Gretchen, of JobsBlog fame, follows me on twitter. Her response? "Congratulations! Sounds like we'll have to do something about that." (Note: Since twitter is public, I don't have a problem reposting her words here). By the end of the day, I had three Microsoft teams contacting me. Among those teams was the Live Search team. Since I was interested in machine learning and information retrieval, I requested that team be the one I interview for.

I wasn't too worried on the day of the phone screening. After all, I had passed two phone screens for each of the three other companies; how hard could this one be? Turns out, it could be pretty hard. The screener started out by asking if I primarily used live search. My response, "No, I prefer Google." Once it escaped my mouth I immediately knew I bombed. How could I interview for a product that I didn't even use! She then asked if I had ever used Live Search, to which I responded positively. I told her I didn't see much difference in the results, which was true. She then moved on to the "coding" question. I won't go into the question, but I will say I didn't do too well on it. I started out trying to use a dynamic programming algorithm. She quickly informed me that the problem could be solved in linear time. Ouch! We worked on the program for quite some time. I got down the right path, but needed quite a bit of help. She then took questions from me and the interview was over. I knew I wouldn't be moving to the second round. I even sent out a few text messages saying "When interviewing with Microsoft, the answer to 'Do you use live search?' is not 'No, I prefer Google'".

A few days later I was driving my family to a local water park when I got the call from Microsoft. They wanted to fly me out! Wow! Apparently it is OK to use Google after all! I certainly didn't expect that. I was already going to be in the Seattle area for my interview with Amazon, so I asked if they could schedule their interview at the same time. It required some fast moving on their part as my interview with Amazon was only a week away. However, they responded brilliantly and set up my accommodations and new return flight. The only thing left for me to do was choose which teams inside of live search I would prefer to interview with. They gave me a list of teams and their descriptions and I ranked them.

At this point, I'll skip over the Amazon interview and move forward in time to the day before the Microsoft interview. Amazon does not provide a rental car, but instead reimburses you for taxis. Therefore, I had to take a Taxi back to the airport and then get the rental car from Microsoft. From there, I drove to Redmond and found my hotel. It was in the Redmond Town Center, which provided a great venue for eating and shopping. I got there in the afternoon and I found greek diner in the town center. After lunch I went back to my hotel and watched some Ars Digita University algorithms classes. In addition, I had also spent some time reading the CLRS Algorithms book. Those two things, coupled with an online MIT course on algorithms would be my primary study guide. Unlike Ben, I didn't work too many problems out on my own, just geeked out over videos :) On a side note, the hotel that Amazon provided didn't have free in-room internet, so it was nice to be in a hotel that did.

At this point, my worst nightmare happened. My stomach began to churn and I started spending more time in the bathroom than out. Why did this keep happening to me? Was it nerves or do I REALLY not like Seattle food? I tried a couple of times to wander around the Redmond Town Center, but each time I kept having to run (literally) back to my hotel room. If this didn't pass by the next day, I was going to just die.

Luckily it went away. I ended up eating something light for supper instead of all the greek and italian food I'd been eating. That seemed to help. By the morning, I was going to the bathroom at a much slower pace, so maybe I'd be ok.

I left very early in order to get to Building 19 on time. I didn't map out the route the day before, so I wanted to be sure I could find it. I'm glad I did leave early because the signs to it aren't overly visible and I looped the Microsoft campus a few times before finding the right building.

The receptionist inside the Lobby of Bldg 19 took my name. I commented on her ear thingies. She had things in her earlobes like they have in Africa. I asked her what they were called and she said, "Gauges." I told her I was from Arkansas and we don't see too many things like that, but I thought they were cool. She thanked me and pointed to the waiting area. Yes, right, don't flirt with the receptionist...go sit down.

The waiting area came complete with an XBox 360 and a copy of Guitar Hero, which another candidate was playing. Well, at least I thought it was a candidate. I have to admit, she was really tearing up Guitar Hero - definitely a pro! After her turn ended, she looked back over at the receptionist and said, "Ok, your turn!". It turns out she was the OTHER receptionist. They swapped places and Gauge Girl began playing Guitar Hero (well, she offered it to me first, but I politely refused). Sadly, I began wondering if that was a test. Maybe they only hired people that played Guitar Hero when given the chance? (yeah, I'm sad like that)

After a bit of waiting, my recruiter came in. He took me back to his office and we began to talk about Microsoft. He gave me a great spiel about the company; he was a good salesman. We ended up talking longer than we should have and I had to hurry to get to a bus. Unfortunately, all the buses were gone and we had to wait for one to come back. It made me late to my first appointment :( He said not to worry, he would call over and tell them I was going to be late. Furthermore, like Ben, I was give a schedule that only went until 2:00. If I didn't perform, I'd be done then.

My first interview went ok. I never do great in the mornings, but I answered his questions satisfactorily. I forgot one simple case which finally came to me, but other than that, I did fine. I mentioned this failing to the next interviewer who said not to worry about it. The next interview was more challenging, I had read a bit about what he was asking, so I had some background, which I explained to him. However, I only had the broad theory, not the intricate details, so we proceeded to hammer out the details over the board. It was actually a lot of fun because I knew certain things to be true, but didn't know why. We discovered why together over the board. It caused a lot of "Aha!" moments. The only downside is that I missed a key part that caused my runtime to explode. I figured this out as he was chatting with the next interviewer and when they returned I mentioned the optimization to him. He nodded his agreement and passed me off.

At this point, it was lunchtime. My interviewer took me to the cafeteria. I got Chinese food because I thought I could eat the rice without it upsetting my stomach. We talked over lunch and I didn't eat much. We mainly discussed coding styles, agile methods, etc... Turns out he was interested in a book club I had started with my current company because he was running one for his team.

After lunch, we returned to his office for some interface design. I teach a UML class at The University of Arkansas at Little Rock so I sketched out my interface and design in UML. We went into detail around some of the decisions, like whether to use a visitor pattern and factory pattern. I think I did ok, but it is hard to design an interface without seeing use cases for it first. I mentioned this toward the end and he agreed. At the end of this interview it was 2:00...and...he took me to the next interview!

During this interview I was back to coding. Actually, I never got around to coding too much as I spent most of my time determining the algorithm. This is a big difference from my first Microsoft interview as I would have gone straight to the code. In this interview, I stepped back, looked at a number of examples and came up with the right solution first. I coded it pretty quickly, but no major mistakes. He showed me some of the cool things his team had been working on. I was really impressed! Then, he took me to the next interviewer. This interviewer focused me on a "real world" problem. In other words, this problem was one that they had seen and solved in the past. It took me about half the interview, but I came up with the solution. He seemed impressed and said that not many of their interviewers come up with that solution and it is the one that they actually used in production. I was pretty pleased with myself at that point. We spent the rest of the time talking about their projects, team structure, etc... It turns out that both teams I interviewed with spend a lot of time working with Microsoft Research, which is really cool for an academic like me :)

That was the last interview before the "big boss", who took me to get a drink and a snack. I was hungry since I didn't eat much lunch, so I took him up on a granola bar and a bottle of water. He spent a lot of time telling me about Microsoft and asking me about my previous experience and the work I did with my current company. I told him what I could without violating any NDAs. He seemed pleased with what I told him and I was very impressed with what he was saying about the future of the team. He described a lot of their internal systems and frameworks, all of which excited me. Like the recruiter, he was a great salesman. That must be a Microsoft thing :)

After our discussion, he said that I should meet the other team's "big boss" (my words, not his). He left me in the lobby of his building and went to hunt the other one down. Turns out the other "big boss" had just gotten done playing softball with the interns and needed to clean up, but offered to take me to dinner. I graciously accepted and sat down to wait as he got ready. I went to eat with him and one of his team leads (who I had interviewed with previously) at an Italian restaurant in the Redmond Town Center. We talked about Microsoft, the Yahoo deal, Google, our mutual desire to WIN, etc... He was also a great salesman.

I was pretty pumped after leaving there that night and couldn't sleep a bit on my red-eye flight back home. I called my wife and told her that I was pretty sure we'd have an offer from Microsoft to consider. Turns out we would also have an offer from Amazon.

I won't go too much into my decision making process other than to say that I did not like the Silicon Valley area. It just felt dirty to me. I was much more at home in Seattle. I liked the contemporary vibe and the fact that there were actual trees. Lots of trees. Yeah, I know it rains, but I don't like the sun much, anyway :) Therefore, though the Yahoo! job was very attractive, I just could not accept it. My decision was between Amazon and Microsoft.

At one point, I thought I wasn't going to accept any of the offers. We are settled, the kids are in school, we own our home, and life isn't too bad. However, I think the ability to work with some amazingly smart people and have Microsoft on the resume is too good to pass up. It is not often that you get to work with internet scale data. My work at Acxiom is on billions of records, but nothing like what you see when you consider search. The playing field is very, very different and you have to think WAY outside the box, which I love to do. Moreover, I think it would benefit our kids to be in an environment like Seattle. There's a lot to see and do there and there are many more opportunities there than there are here in Arkansas. Finally, the school systems there are very good and I think the kids will benefit greatly from that.

I start on August 25th and I am very excited. I'll be sad to leave a great team behind, but I know they wish me the best as well. Now, I'm looking forward to starting the next phase of my life as a member of the Live Search team. Google, look out!

New Job

I'm excited to announce that I am joining Microsoft to work on their Microsoft Live Search Engine. It's going to be a big transition, but I've never lived in the northwest, so it is a very exciting time as well. I begin there on August 25 and am very excited!

Please keep me in your prayers during this exciting, but stressful time.